The Meaning of Romans 1:21 Explained

Romans 1:21

KJV: Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.

YLT: because, having known God they did not glorify Him as God, nor gave thanks, but were made vain in their reasonings, and their unintelligent heart was darkened,

Darby: Because, knowing God, they glorified him not as God, neither were thankful; but fell into folly in their thoughts, and their heart without understanding was darkened:

ASV: because that, knowing God, they glorified him not as God, neither gave thanks; but became vain in their reasonings, and their senseless heart was darkened.

KJV Reverse Interlinear

Because  that, when they knew  God,  they glorified  [him] not  as  God,  neither  were thankful;  but  became vain  in  their  imaginations,  and  their  foolish  heart  was darkened. 

What does Romans 1:21 Mean?

Context Summary

Romans 1:13-23 - The Only Power Of Salvation
We owe everything to our Lord, but since we can make Him no direct return, He has made men His residuary legatees. We are to think of others as having a claim upon us for His dear sake. In helping them, we repay Him. But note the Apostle's humility-as much as in me is, Romans 1:15. Paul was not indifferent to the claims of intellectual culture. He had been thoroughly trained in Hebrew and Greek literature. The high culture of the Roman world was appreciated by the student of Gamaliel for what it was worth; but he was not ashamed to preach the gospel in its capital because it carried with it the divine dynamic. It was power unto salvation. The Stoic, for instance, had a high ethical code, but it was ineffective for want of the driving power of Pentecost. The one condition is faith-to everyone that believeth, Romans 1:16.
Every man born into the world has an opportunity of knowing right and wrong from the inner witness of conscience, and of learning something of God from His works. Men will be judged by their attitude toward these two luminaries. Notice, however, that sad, strong word! Too many hold down the truth, Romans 1:18, r.v. They deliberately endeavor to throttle it. [source]

Chapter Summary: Romans 1

1  Paul commends his calling to the Romans;
9  and his desire to come to them
16  What his gospel is
18  God is angry with sin
21  What were the sins of mankind

Greek Commentary for Romans 1:21

Because that [διοτι]
As in Romans 1:19. [source]
Knowing God [γνοντες τον τεον]
Second aorist active participle of γινωσκω — ginōskō to know by personal experience. Definite statement that originally men had some knowledge of God. No people, however degraded, have yet been found without some yearning after a god, a seeking to find the true God and get back to him as Paul said in Athens (Acts 17:27). Glorified not as God (ουχ ως τεον εδοχασαν — ouch hōs theon edoxasan). They knew more than they did. This is the reason for the condemnation of the heathen (Romans 2:12-16), the failure to do what they know. Their senseless heart Καρδια — Kardia is the most comprehensive term for all our faculties whether feeling (Romans 9:2), will (1 Corinthians 4:5), intellect (Romans 10:6). It may be the home of the Holy Spirit (Romans 5:5) or of evil desires (Romans 1:24). See notes on Mark 7:21. for list of vices that come “out of the heart.” Ασυνετος — Asunetos is a verbal adjective from συνιημι — suniēmi to put together, and α — a privative, unintelligent, not able to put together the manifest evidence about God (Romans 1:20). So darkness settled down on their hearts (εσκοτιστη — eskotisthē first aorist ingressive passive of σκοτιζω — skotizō to darken). [source]
Glorified not as God [ουχ ως τεον εδοχασαν]
They knew more than they did. This is the reason for the condemnation of the heathen (Romans 2:12-16), the failure to do what they know. [source]
Their senseless heart [η ασυνετος αυτων καρδια]
Καρδια — Kardia is the most comprehensive term for all our faculties whether feeling (Romans 9:2), will (1 Corinthians 4:5), intellect (Romans 10:6). It may be the home of the Holy Spirit (Romans 5:5) or of evil desires (Romans 1:24). See notes on Mark 7:21. for list of vices that come “out of the heart.” Ασυνετος — Asunetos is a verbal adjective from συνιημι — suniēmi to put together, and α — a privative, unintelligent, not able to put together the manifest evidence about God (Romans 1:20). So darkness settled down on their hearts (εσκοτιστη — eskotisthē first aorist ingressive passive of σκοτιζω — skotizō to darken). [source]
Knowing - glorified not []
“I think it may be proved from facts that any given people, down to the lowest savages, has at any period of its life known far more than it has done: known quite enough to have enabled it to have got on comfortably, thriven and developed, if it had only done what no man does, all that it knew it ought to do and could do” (Charles Kingsley, “The Roman and the Teuton”). [source]
Became vain [ἐματαιώθησαν]
Vain things ( μάταια ) was the Jews' name for idols. Compare Acts 4:15. Their ideas and conceptions of God had no intrinsic value corresponding with the truth. “The understanding was reduced to work in vacuo. It rendered itself in a way futile ” (Godet). [source]
Foolish [ἀσύνετος]
See on συνετός prudent Matthew 11:25, and the kindred word σύνεσις understandingsee on Mark 12:33; see on Luke 2:47. They did not combine the facts which were patent to their observation. [source]
Imaginations [διαλογισμοῖς]
Rev., better, reasonings. See on Matthew 15:19; see on Mark 7:21; see on James 2:4. [source]
Heart [καρδία]
The heart is, first, the physical organ, the center of the circulation of the blood. Hence, the seat and center of physical life. In the former sense it does not occur in the New Testament. As denoting the vigor and sense of physical life, see Acts 14:17; James 5:5; Luke 21:34. It is used fifty-two times by Paul. Never used like ψυχή , soul, to denote the individual subject of personal life, so that it can be exchanged with the personal pronoun (Acts 2:43; Acts 3:23; Romans 13:1); nor like πνεῦμα spiritto denote the divinely-given principle of life. -DIVIDER-
-DIVIDER-
It is the central seat and organ of the personal life ( ψυχή ) of man regarded in and by himself. Hence it is commonly accompanied with the possessive pronouns, my, his, thy, etc. -DIVIDER-
-DIVIDER-
Like our heart it denotes the seat of feeling as contrasted with intelligence. 2 Corinthians 2:4; Romans 9:2; Romans 10:1; 2 Corinthians 6:11; Philemon 1:7. But it is not limited to this. It is also the seat of mental action, feeling, thinking, willing. It is used - -DIVIDER-
1. Of intelligence, Romans 1:21; 2 Corinthians 3:15; 2 Corinthians 4:6; Ephesians 1:18. -DIVIDER-
-DIVIDER-
2. Of moral choice, 1 Corinthians 7:37; 2 Corinthians 9:7. -DIVIDER-
-DIVIDER-
3. As giving impulse and character to action, Romans 6:17; Ephesians 6:5; Colossians 3:22; 1 Timothy 1:5; 2 Timothy 2:22. The work of the law is written on the heart, Romans 2:15. The Corinthian Church is inscribed as Christ's epistle on hearts of flesh, 2 Corinthians 3:2-3. -DIVIDER-
-DIVIDER-
4. Specially, it is the seat of the divine Spirit, Galatians 4:6; Romans 5:5; 2 Corinthians 1:22. It is the sphere of His various operations, directing, comforting, establishing, etc., Philemon 4:7; Colossians 3:15; 1 Thessalonians 3:13; 2 Thessalonians 2:17; 2 Thessalonians 3:5. It is the seat of faith, and the organ of spiritual praise, Romans 10:9; Ephesians 5:19; Colossians 3:16. -DIVIDER-
-DIVIDER-
It is equivalent to the inner man, Ephesians 3:16, Ephesians 3:17. Its characteristic is being hidden, Romans 2:28, Romans 2:29; Romans 8:27; 1 Corinthians 4:5; 1 Corinthians 14:25. -DIVIDER-
-DIVIDER-
It is contrasted with the face, 1 Thessalonians 2:17; 2 Corinthians 5:12; and with the mouth, Romans 10:8. -DIVIDER-
-DIVIDER-
[source]

Reverse Greek Commentary Search for Romans 1:21

John 14:1 Heart [καρδία]
Never used in the New Testament, as in the Septuagint, of the mere physical organ, though sometimes of the vigor and sense of physical life (Acts 14:17; James 5:5; Luke 21:34). Generally, the center of our complex being - physical, moral, spiritual, and intellectual. See on Mark 12:30. The immediate organ by which man lives his personal life, and where that entire personal life concentrates itself. It is thus used sometimes as parallel to ψυχή , the individual life, and to πνεῦμα theprinciple of life, which manifests itself in the ψυχή . Strictly, καρδία is the immediate organ of ψυχή , occupying a mediating position between it and πνεῦμα . In the heart ( καρδία ) the spirit ( πνεῦμα ), which is the distinctive principle of the life or soul ( ψυχή ), has the seat of its activity. Emotions of joy or sorrow are thus ascribed both to the heart and to the soul. Compare John 14:27, “Let not your heart ( καρδιά ) be troubled;” and John 12:27, “Now is my soul ( ψυχή ) troubled.” The heart is the focus of the religious life (Matthew 22:37; Luke 6:45; 2 Timothy 2:22). It is the sphere of the operation of grace (Matthew 13:19; Luke 8:15; Luke 24:32; Acts 2:37; Romans 10:9, Romans 10:10). Also of the opposite principle (John 13:2; Acts 5:3). Used also as the seat of the understanding; the faculty of intelligence as applied to divine things (Matthew 13:15; Romans 1:21; Mark 8:17). [source]
John 1:5 In the darkness [ἐν τῇ σκοτίᾳ]
Σκοτία , darkness, is a word peculiar to later Greek, and used in the New Testament almost exclusively by John. It occurs once in Matthew 10:27, and once in Luke 12:3. The more common New Testament word is σκότος , from the same root, which appears in σκιά , shadow, and σκηνή , tent. Another word for darkness, ζόφος , occurs only in Peter and Jude (2 Peter 2:4, 2 Peter 2:17; Judges 1:6, Judges 1:13). See on 2 Peter 2:4. The two words are combined in the phrase blackness of darkness (2 Peter 2:17; Judges 1:13). In classical Greek σκότος , as distinguished from ζόφος , is the stronger term, denoting the condition of darkness as opposed to light in nature. Hence of death, of the condition before birth; of night. Ζόφος , which is mainly a poetical term, signifies gloom, half-darkness, nebulousness. Here the stronger word is used. The darkness of sin is deep. The moral condition which opposes itself to divine light is utterly dark. The very light that is in it is darkness. Its condition is the opposite of that happy state of humanity indicated in John 1:4, when the life was the light of men; it is a condition in which mankind has become the prey of falsehood, folly and sin. Compare 1 John 1:9-10. Romans 1:21, Romans 1:22. [source]
Romans 6:17 From the heart []
See on Romans 1:21. [source]
Romans 3:11 Understandeth [συνιῶν]
See on foolish, Romans 1:21. [source]
Romans 10:19 By a foolish nation [ἐπὶ ἔθνει ἀσυνέτῳ]
Lit., upon a foolish nation as the basis of the exasperation. For foolish, see on Romans 1:21. [source]
Romans 1:21 Heart [καρδία]
The heart is, first, the physical organ, the center of the circulation of the blood. Hence, the seat and center of physical life. In the former sense it does not occur in the New Testament. As denoting the vigor and sense of physical life, see Acts 14:17; James 5:5; Luke 21:34. It is used fifty-two times by Paul. Never used like ψυχή , soul, to denote the individual subject of personal life, so that it can be exchanged with the personal pronoun (Acts 2:43; Acts 3:23; Romans 13:1); nor like πνεῦμα spiritto denote the divinely-given principle of life. -DIVIDER-
-DIVIDER-
It is the central seat and organ of the personal life ( ψυχή ) of man regarded in and by himself. Hence it is commonly accompanied with the possessive pronouns, my, his, thy, etc. -DIVIDER-
-DIVIDER-
Like our heart it denotes the seat of feeling as contrasted with intelligence. 2 Corinthians 2:4; Romans 9:2; Romans 10:1; 2 Corinthians 6:11; Philemon 1:7. But it is not limited to this. It is also the seat of mental action, feeling, thinking, willing. It is used - -DIVIDER-
1. Of intelligence, Romans 1:21; 2 Corinthians 3:15; 2 Corinthians 4:6; Ephesians 1:18. -DIVIDER-
-DIVIDER-
2. Of moral choice, 1 Corinthians 7:37; 2 Corinthians 9:7. -DIVIDER-
-DIVIDER-
3. As giving impulse and character to action, Romans 6:17; Ephesians 6:5; Colossians 3:22; 1 Timothy 1:5; 2 Timothy 2:22. The work of the law is written on the heart, Romans 2:15. The Corinthian Church is inscribed as Christ's epistle on hearts of flesh, 2 Corinthians 3:2-3. -DIVIDER-
-DIVIDER-
4. Specially, it is the seat of the divine Spirit, Galatians 4:6; Romans 5:5; 2 Corinthians 1:22. It is the sphere of His various operations, directing, comforting, establishing, etc., Philemon 4:7; Colossians 3:15; 1 Thessalonians 3:13; 2 Thessalonians 2:17; 2 Thessalonians 3:5. It is the seat of faith, and the organ of spiritual praise, Romans 10:9; Ephesians 5:19; Colossians 3:16. -DIVIDER-
-DIVIDER-
It is equivalent to the inner man, Ephesians 3:16, Ephesians 3:17. Its characteristic is being hidden, Romans 2:28, Romans 2:29; Romans 8:27; 1 Corinthians 4:5; 1 Corinthians 14:25. -DIVIDER-
-DIVIDER-
It is contrasted with the face, 1 Thessalonians 2:17; 2 Corinthians 5:12; and with the mouth, Romans 10:8. -DIVIDER-
-DIVIDER-
[source]

Romans 1:18 Hold [κατεχόντων]
Not possess: compare Romans 1:21. Rev., correctly, hold down; i.e., hinder or repress. Compare 2 Thessalonians 2:6, 2 Thessalonians 2:7; Luke 4:42. [source]
Romans 1:31 Without understanding [ασυνετους]
Same word in Romans 1:21. [source]
Romans 9:2 Heart []
See on Romans 1:21. [source]
Romans 2:1 Without excuse [αναπολογητος]
See note on Romans 1:21. Whosoever thou art that judgest (πας ο κρινων — pas ho krinōn). Literally, “every one that judgest,” vocative case in apposition with αντρωπε — anthrōpe Paul begins his discussion of the failure of the Jew to attain to the God-kind of righteousness (2:1-3:20) with a general statement applicable to all as he did (Romans 1:18) in the discussion of the failure of the Gentiles (Lightfoot). The Gentile is readily condemned by the Jew when he sins and equally so is the Jew condemned by the Gentile in like case. Κρινω — Krinō does not of itself mean to condemn, but to pick out, separate, approve, determine, pronounce judgment, condemn (if proper). Another Literally, “the other man.” The notion of two in the word, one criticizing the other. Thou condemnest thyself (σεαυτον κατακρινεις — seauton katakrineis). Note κατα — kata here with κρινω — krinō to make plain the adverse judgment. For Explanatory reason for the preceding statement. The critic practises (πρασσεις — prasseis not single acts ποιεω — poieō but the habit πρασσω — prassō) the same things that he condemns. [source]
1 Corinthians 2:9 Heart [καρδίαν]
See on Romans 1:21. [source]
1 Corinthians 2:11 Spirit [πνεῦμα]
See on Romans 8:4. The things of God can be recognized only by the highest element of the human personality. They have not entered into the heart ( καρδία , see on Romans 1:21), but into the spirit, which is the highest and principal point of contact with the Spirit of God. [source]
1 Corinthians 2:9 Heart [καρδιαν]
(καρδιαν — kardian) here as in Romans 1:21 is more than emotion. The Gnostics used this passage to support their teaching of esoteric doctrine as Hegesippus shows. Lightfoot thinks that probably the apocryphal Ascension of Isaiah and Apocalypse of Elias were Gnostic and so quoted this passage of Paul to support their position. But the next verse shows that Paul uses it of what is now revealed and made plain, not of mysteries still unknown. [source]
1 Corinthians 2:9 Whatsoever [οσα]
A climax to the preceding relative clause (Findlay). Prepared (ητοιμασεν — hētoimasen). First aorist active indicative of ετοιμαζω — hetoimazō The only instance where Paul uses this verb of God, though it occurs of final glory (Luke 2:31; Matthew 20:23; Matthew 25:34; Mark 10:40; Hebrews 11:16) and of final misery (Matthew 25:41). But here undoubtedly the dominant idea is the present blessing to these who love God (1 Corinthians 1:5-7). Heart (καρδιαν — kardian) here as in Romans 1:21 is more than emotion. The Gnostics used this passage to support their teaching of esoteric doctrine as Hegesippus shows. Lightfoot thinks that probably the apocryphal Ascension of Isaiah and Apocalypse of Elias were Gnostic and so quoted this passage of Paul to support their position. But the next verse shows that Paul uses it of what is now revealed and made plain, not of mysteries still unknown. [source]
Ephesians 4:17 Vanity of their mind [ματαιότητι τοῦ νοὸς αὐτῶν]
For vanity see on Romans 1:21; see on Romans 8:20. For mind, see on Romans 7:23. [source]
Ephesians 1:18 The eyes of your understanding being enlightened [πεφωτισμένους τοὺς ὀφθαλμοὺς τῆς καρδίας ὑμῶν]
Rev., eyes of your heart. Lit., being enlightened as to the eyes of your heart; enlightened being joined with you (Ephesians 1:17) by a somewhat irregular construction: may give unto you being enlightened. For a similar construction see Acts 15:22. The phrase eyes of the heart occurs nowhere else in the New Testament. Plato has eye of the soul ( ψυχῆς , “Sophist,” 254). Ovid, speaking of Pythagoras, says: “With his mind he approached the gods, though far removed in heaven, and what nature denied to human sight, he drew forth with the eyes of his heart” (“Metamorphoses,” xv., 62-64). Heart is not merely the seat of emotion, as in popular usage, but of thought and will. See on Romans 1:21. The particular aspect in which its activity is viewed, perception or cognition, is determined by what follows, “that ye may know,” etc. [source]
Philippians 4:7 Hearts - minds [καρδίας - νοήματα]
For hearts, see on Romans 1:21. For minds, Rev., thoughts, see on 2 Corinthians 3:14. The guardianship is over the source and the issues of thought and will. “Your hearts and their fruits” (Alford). [source]
Colossians 3:23 Heartily [ἐκ ψυχῆς]
Lit., from the soul. With a personal interest. Note that the apostle uses both heart ( καρδίας , Colossians 3:22) and soul ( ψυχῆς ); and in Ephesians 6:7, adds μετ ' εὐνοίας withgood disposition (A.V., good will ). See on Romans 11:3; see on Romans 7:23; see on Romans 1:21. Compare σύμψυχοι ofone accord, Philemon 2:2; ἰσόψυχον like-minded Philemon 2:20; μιᾷ ψυχῇ withone mind, Philemon 1:27. [source]
Colossians 2:7 Thanksgiving [εὐχαριστίᾳ]
For Paul's emphasis on thanksgiving, see Romans 1:21; Romans 14:6; 2 Corinthians 1:11; 2 Corinthians 4:15; 2 Corinthians 9:11, 2 Corinthians 9:12; Ephesians 5:20; 1 Timothy 2:1, etc. Εὐχαριστός thankful εὐχαριστεῖν togive thanks, εὐχαριστία thanksgivingare found only in Paul's writings. [source]
Colossians 1:9 Knowledge [ἐπίγνωσιν]
See on Romans 3:20; see on Philemon 1:6. Full knowledge. See Romans 1:21, Romans 1:28; 1 Corinthians 13:12, where Paul contrasts γινώσκειν toknow γνῶσις knowledgewith ἐπιγινώσκειν toknow fully, ἐπίγνωσις fullknowledge. Here appropriate to the knowledge of God in Christ as the perfection of knowledge. [source]
2 Thessalonians 3:5 Hearts [καρδίας]
See on Romans 1:21; see on Romans 10:10; see on Ephesians 1:18. [source]
2 Thessalonians 1:8 On them that know not God - obey not the gospel [τοῖς μὴ εἰδόσι θεὸν - τοῖς μὴ ὑπακούουσιν τῷ εὐγγελίῳ]
To know God is to know him as the one, true God as distinguished from false gods; to know his will, his holiness, his hatred of sin, and his saving intent toward mankind. Two words are used of such knowledge, εἰδέναι and γινώσκειν . Both are applied to the heathen and to Christians, and both are used of the Jews' knowledge of God. Ἑιδέναι , of heathen, Galatians 4:8; 1 Thessalonians 4:5; 2 Thessalonians 1:8. Γινώσκειν of heathen, Romans 1:21; 1 Corinthians 1:21. Ἑιδέναι , of Christ and Christians, John 7:29, John 8:19, John 8:55; John 14:7. Γινώσκειν of Christ and Christians, Galatians 4:9; 1 John 2:13, 1 John 2:14; 1 John 4:6, 1 John 4:7, 1 John 4:8; John 10:15; John 17:3. In John, γινώσκειν of Jews who do not know the Father, John 16:3; John 8:55: εἰδέναι , John 7:28; John 8:19; John 15:21. The two are combined, John 1:26; John 7:27; John 8:55; 2 Corinthians 5:16. A distinction is asserted between γινώσκειν as knowledge grounded in personal experience, apprehension of external impressions - and εἰδέμαι purely mental perception in contrast with conjecture or knowledge derived from others. There are doubtless passages which bear out this distinction (see on John 2:24), but it is impossible to carry it rigidly through the N.T. In the two classes, - those who know not God and those who obey not the gospel, - it is not probable that Paul has in mind a distinction between Jews and Gentiles. The Jews were not ignorant of God, yet they are described by John as not knowing him. The Gentiles are described by Paul as knowing God, but as refusing to glorify him as God (Romans 1:21). Paul rather describes here the subjects of God's judgment as one class, but under different aspects. [source]
1 Timothy 2:4 Come to the knowledge of the truth [εἰς ἐπίγνωσιν ἀληθείας ἐλθεῖν]
The phrase only here and 2 Timothy 3:7. Ἑπίγνωσις is a favorite Pauline word. See on Romans 3:20; see on Colossians 1:9; see on 1 Timothy 2:4; see on 1 Timothy 4:3. It signifies advanced or full knowledge. The difference between the simple γνῶσις and the compound word is illustrated in Romans 1:21, Romans 1:28, and 1 Corinthians 13:12. In N.T. always of the knowledge of things ethical or divine, and never ascribed to God. For ἀλήθεια truthsee on sound doctrine, 1 Timothy 1:10. It appears 14 times in the Pastorals, and always without a defining genitive. So, often in Paul, but several times with a defining genitive, as truth of God, of Christ, of the gospel. The logical relation in the writer's mind between salvation and the knowledge of the truth is not quite clear. Knowledge of the truth may be regarded as the means of salvation, or it may be the ideal goal of the whole saving work. See 1 Corinthians 13:12; Philemon 3:8; John 17:3. The latter is more in accord with the general drift of teaching in these Epistles. [source]
1 Timothy 1:5 Out of a pure heart [ἐκ καθαρᾶς καρδίας]
Comp. Luke 10:27, “Thou shalt love the Lord thy God out of they whole heart ( ἐξ ὅλης καρδίας σου ), and in or with ( ἐν ) thy whole soul,” etc. For a pure heart, comp. 2 Timothy 2:22. Καθαρός purein Paul only Romans 14:20. The phrase a pure heart occurs, outside of the Pastorals only in 1 Peter 1:22. For καρδία heartsee on Romans 1:21. [source]
Titus 3:9 Vain [μάταιοι]
Only here in Pastorals. Twice in Paul, 1 Corinthians 3:20, cit.; 1 Corinthians 15:17(note). Very frequent in lxx. The sense is aimless or resultless, as μάταιος εὐχή aprayer which cannot obtain fulfilment. The questions, genealogies, etc., lead to no attainment or advancement in godliness. Comp. ματαιολογία jangling 1 Timothy 1:6; ματαιολόγοι vaintalkers, 1 Timothy 1:10; ματαιότης vanity Romans 8:20; Ephesians 4:17; ἐματαιώθησαν weremade vain, Romans 1:21; μάτην invain, Matthew 15:9. [source]
Titus 3:3 Foolish [ανοητοι]
See Romans 1:14, Romans 1:21. Disobedient (απειτεις — apeitheis). See note on Romans 1:30. Deceived Present passive participle of πλαναω — planaō though the middle is possible. Divers lusts (ηδοναις ποικιλαις — hēdonais poikilais). “Pleasures” (ηδοναις — hēdonais from ηδομαι — hēdomai old word, in N.T. only here, Luke 8:14; James 4:1, James 4:3; 2 Peter 2:13). Ποικιλαις — Poikilais (old word) is many-coloured as in Mark 1:34; James 1:2; 2 Timothy 3:6, etc. Living See note on 1 Timothy 3:6 (supply βιον — bion). In malice (εν κακιαι — en kakiāi). See note on Romans 1:29. Envy See note on Romans 1:29. Hateful (στυγητοι — stugētoi). Late passive verbal from στυγεω — stugeō to hate. In Philo, only here in N.T. Hating one another Active sense and natural result of being “hateful.” [source]
Hebrews 8:10 Mind [διάνοιαν]
The moral understanding. See on Mark 12:30; see on Luke 1:51. Hearts, καρδίας , see on Romans 1:21; see on Romans 10:10. [source]
James 2:4 Judges with evil thoughts [κριται διαλογισμων πονηρων]
Descriptive genitive as in James 1:25. Διαλογισμος — Dialogismos is an old word for reasoning (Romans 1:21). Reasoning is not necessarily evil, but see Matthew 15:19 (πονηροι — ponēroi) and Mark 7:21 (κακοι — kakoi) for evil reasonings, and 1 Timothy 2:8 without an adjective. See James 1:8; James 4:8 for διπσυχος — dipsuchos They are guilty of partiality (a divided mind) as between the two strangers. [source]
2 Peter 2:4 Angels when they sinned [αγγελων αμαρτησαντων]
Genitive case after επεισατο — epheisato (first aorist middle indicative of πειδομαι — pheidomai) and anarthrous (so more emphatic, even angels), first aorist active participle of αμαρτανω — hamartanō “having sinned.”Cast them down to hell (ταρταρωσας — tartarōsas). First aorist active participle of ταρταροω — tartaroō late word (from ταρταρος — tartaros old word in Homer, Pindar, lxx Job 40:15; 41:23, Philo, inscriptions, the dark and doleful abode of the wicked dead like the Gehenna of the Jews), found here alone save in a scholion on Homer. Ταρταρος — Tartaros occurs in Enoch 20:2 as the place of punishment of the fallen angels, while Gehenna is for apostate Jews.Committed First aorist active indicative of παραδιδωμι — paradidōmi the very form solemnly used by Paul in Romans 1:21, Romans 1:26, Romans 1:28.To pits of darkness (σειροις ζοπου — seirois zophou). οπος — Zophos (kin to γνοποσ νεπος — gnophosσειραις — nephos) is an old word, blackness, gloom of the nether world in Homer, in N.T. only here, 2 Peter 2:17; Judges 1:13; Hebrews 12:18. The MSS. vary between σειρα — seirais (σειροις — seira chain or rope) and σειρος — seirois (Σειροις — seiros old word for pit, underground granary). εις κρισιν τηρουμενους — Seirois is right (Aleph A B C), dative case of destination.To be reserved unto judgment Present (linear action) passive participle of κολαζομενους τηρειν — tēreō “Kept for judgment.” Cf. 1 Peter 1:4. Aleph A have κρισις — kolazomenous tērein as in 2 Peter 2:9. Note krisis (act of judgment). [source]
2 Peter 2:4 Committed [παρεδωκεν]
First aorist active indicative of παραδιδωμι — paradidōmi the very form solemnly used by Paul in Romans 1:21, Romans 1:26, Romans 1:28.To pits of darkness (σειροις ζοπου — seirois zophou). οπος — Zophos (kin to γνοποσ νεπος — gnophosσειραις — nephos) is an old word, blackness, gloom of the nether world in Homer, in N.T. only here, 2 Peter 2:17; Judges 1:13; Hebrews 12:18. The MSS. vary between σειρα — seirais (σειροις — seira chain or rope) and σειρος — seirois (Σειροις — seiros old word for pit, underground granary). εις κρισιν τηρουμενους — Seirois is right (Aleph A B C), dative case of destination.To be reserved unto judgment Present (linear action) passive participle of κολαζομενους τηρειν — tēreō “Kept for judgment.” Cf. 1 Peter 1:4. Aleph A have κρισις — kolazomenous tērein as in 2 Peter 2:9. Note krisis (act of judgment). [source]

What do the individual words in Romans 1:21 mean?

For having known - God not as they glorified [Him] or were thankful but they became futile in the thinking of them and was darkened the foolish heart
Διότι γνόντες τὸν Θεὸν οὐχ ὡς ἐδόξασαν ηὐχαρίστησαν ἀλλὰ ἐματαιώθησαν ἐν τοῖς διαλογισμοῖς αὐτῶν καὶ ἐσκοτίσθη ἀσύνετος καρδία

γνόντες  having  known 
Parse: Verb, Aorist Participle Active, Nominative Masculine Plural
Root: γινώσκω  
Sense: to learn to know, come to know, get a knowledge of perceive, feel.
τὸν  - 
Parse: Article, Accusative Masculine Singular
Root:  
Sense: this, that, these, etc.
Θεὸν  God 
Parse: Noun, Accusative Masculine Singular
Root: θεός  
Sense: a god or goddess, a general name of deities or divinities.
ἐδόξασαν  they  glorified  [Him] 
Parse: Verb, Aorist Indicative Active, 3rd Person Plural
Root: δοξάζω  
Sense: to think, suppose, be of opinion.
ηὐχαρίστησαν  were  thankful 
Parse: Verb, Aorist Indicative Active, 3rd Person Plural
Root: εὐχαριστέω  
Sense: to be grateful, feel thankful.
ἐματαιώθησαν  they  became  futile 
Parse: Verb, Aorist Indicative Passive, 3rd Person Plural
Root: ματαιόω  
Sense: to make empty, vain, foolish.
διαλογισμοῖς  thinking 
Parse: Noun, Dative Masculine Plural
Root: διαλογισμός  
Sense: the thinking of a man deliberating with himself.
αὐτῶν  of  them 
Parse: Personal / Possessive Pronoun, Genitive Masculine 3rd Person Plural
Root: αὐτός  
Sense: himself, herself, themselves, itself.
ἐσκοτίσθη  was  darkened 
Parse: Verb, Aorist Indicative Passive, 3rd Person Singular
Root: σκοτίζομαι  
Sense: to cover with darkness, to darken.
ἀσύνετος  foolish 
Parse: Adjective, Nominative Feminine Singular
Root: ἀσύνετος  
Sense: unintelligent, without understanding, stupid.
καρδία  heart 
Parse: Noun, Nominative Feminine Singular
Root: καρδία  
Sense: the heart.