Synonyms for benefit

Most common

1. Advantage — an advantage; help or aid from something

Other

welfare, good turn, return, subsidy

1. Gain

gain, profit, advance

Other

do good, behoove US, behove UK, befriend, oblige, batten

n. 1
An advantage; help or aid from something.
She can't read, so the voice recording was made for her benefit.
v. 1
To be or to provide a benefit to.

Word family: beneficial benefactor beneficence beneficent beneficiary
Phrases: fringe benefit employee benefit benefit society child benefit marginal benefit

Plural: benefits → advantages, helps, boons, aids…
Past participle: benefited
e.g. benefited → gained, profited, advanced, behooved…

or Benefit?

Benefit is anything that does one good.

J. C. Fernald, English Synonyms and Antonyms (1914)

Use in printed books, per decade from 1850 to 2019.

3 letters: use¹, aid¹
4 letters: good¹, help¹, gain¹, boon¹
5 letters: serve¹, favor², mercy², avail²
6 letters: return², profit², assist², behalf², favour², oblige², batten², behove, behoof
7 letters: service², account², advance², welfare², utility⁴, subsidy³, behoove²
8 letters: interest², blessing², befriend², foredeal
9 letters: advantage³
10 letters: assistance³, percentage³
11 letters: benediction⁴

The small number after each word is its number of syllables (favor² = 2 syllables).