Oui

Adverb

 * 1) yes

Antonyms

 * non

Interjection

 * 1) yes

Thesaurus
OK, Roger, absolutely, all right, alright, alrighty, amen, as you say, assuredly, aye, by all means, certainly, da, exactly, fine, good, good enough, hear, indeed, indeedy, ja, just so, mais oui, most assuredly, naturally, naturellement, of course, okay, positively, precisely, quite, rather, really, right, righto, sure, sure thing, surely, to be sure, truly, very well, well and good, why yes, yea, yeah, yep, yes, yes indeed, yes indeedy, yes sir, yes sirree

Etymology
oïl:, a contraction of o il:, from Vulgar *undefined:, or perhaps rather hoc illud est, an elliptical phrase of response, by semantic erosion. Cognate to Occitan òc:, where the connection to Latin hoc: is clearer.