Why does Paul use three different words for gift besides grace in Rom. 5:15-17?

Question

Why does Paul use three different words for gift besides grace in Rom. 5:15-17?

Is Paul only using these words as synomyms to reduce repitition of the same word, or is there a significance in the different words?

But the free gift [τὸ χάρισμα] is not like the trespass. For if many died through one man’s trespass, much more have the grace [ἡ χάρις] of God and the free gift [ἡ δωρεὰ] by the grace [χάριτι] of that one man Jesus Christ abounded for many. 16 And the free gift [τὸ δώρημα] is not like the result of that one man’s sin. For the judgment following one trespass brought condemnation, but the free gift [τὸ δὲ χάρισμα] following many trespasses brought justification. 17 For if, because of one man’s trespass, death reigned through that one man, much more will those who receive the abundance of grace [τῆς χάριτος] and the free gift [⸄τῆς δωρεᾶς] of righteousness reign in life through the one man Jesus Christ.

Answer 1

Paul proceeded to make a series of comparisons about imputed righteousness through Christ being like imputed sin (Romans 5:21) through Adam. Paul made this comparison five times so that there should be no doubt that in the same way that all became sinners through Adam (Romans 5:19), all who put faith in Christ are made righteousness through Him.

The gift by grace spoken of here and in Romans 5:16 and 18 is clearly stated in Romans 5:17. It is the gift of righteousness.

The religious world has basically accepted this truth of inherited sin from Adam, but this truth of inherited righteousness through the new birth is arguably still a mystery to some. Yet Paul was saying that if one is true, then so is the other. These truths are like two sides of one coin. If you accept one truth, you have to accept the other.

These are five comparisons (Romans 5:15-19), but they are opposite comparisons. Adam’s sin brought things from good to bad, but Jesus brought things from bad to good. The results are opposite extremes, but the principle involved in both is the same. In the same way that Adam was able to pass sin (again, see Romans 5:21) and its consequences on to his descendants, so Jesus is able to pass righteousness and all its benefits on to those who put faith in Him.

So in making these comparisons, the use of differing words for ‘gift’ has purpose, to emphasis the comparison, to ‘drive’ the point ‘home’.

Interestingly - this comparison is repeated again in Romans 5:21

Answer 2

Romans 5:

15 But the free gift [τὸ χάρισμα] is not like the trespass. For if many died through one man’s trespass, much more have the grace [ἡ χάρις] of God and the free gift [ἡ δωρεὰ] by the grace [χάριτι] of that one man Jesus Christ abounded for many.

The Greek word for grace is G5485 χάρις (charis).
χάρισμα is G5486 charisma, or grace-gift.
G1431 δωρεά dórea is a (generic) free gift. By generic, I mean not specifically dependent on χάρις.

This verse equates grace-gift and free gift in grace:
τὸ χάρισμα = ἡ δωρεὰ ἐν χάριτι
In this verse, Paul was just saying the same thing with different words for emphasis.

Next verse:

16 And the free gift [τὸ δώρημα] is not like the result of that one man’s sin. For the judgment following one trespass brought condemnation, but [δὲ] the free gift [τὸ χάρισμα] following many trespasses brought justification.

G1434 δώρημα dóréma comes from verb
G1433 δωρέομαι dóreomai meaning to bestow which comes from
G1325 dídōmi to give and G1431 (dórea genericfree gift). So, δώρημα is a noun meaning a bestowed (generic) free gift.

Both δωρεά and δώρημα mean genericfree gift. The latter carries an extra sense of endowment.

This verse equates grace-gift with the gift of endowment:
τὸ χάρισμα = τὸ δώρημα

Next verse:

17 For if, because of one man’s trespass, death reigned through that one man, much more will those who receive the abundance of grace [τῆς χάριτος] and the free gift of righteousness [τῆς δωρεᾶς τῆς δικαιοσύνης] reign in life through the one man Jesus Christ.

This verse associates the generic free gift as free gift of righteousness based on grace:
τῆς δωρεᾶς τῆς δικαιοσύνης

Why does Paul use three different words for gift besides grace in Rom. 5:15-17?

There are 3 words for gift:

1. δωρεά is a generic free gift.
2. δώρημα is a bestowed generic free gift.
3. χάρισμα is a special Grace-dependent free gift.

Each word has its nuance. Together, they are very expressive.

Is Paul only using these words as synonyms to reduce repetition of the same word?

The individual words are not synonyms. Dave's answer is correct :) Paul used them to make equations and associations to grace and righteousness.

Is there significance in the different words?

Yes, it makes the passage richer and more expressive—as Dave put it: to ‘drive’ the point ‘home’ :) Unfortunately, the English translations can't do them full justice :(