suit has 13 distinct synonyms spread across 6 of its 10 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a set of garments (usually including a jacket and trousers or skirt) for outerwear all of the same fabric and color
“they buried him in his best suit”
a comprehensive term for any proceeding in a court of law whereby an individual seeks a legal remedy
“the family brought suit against the landlord”
(slang) a businessman dressed in a business suit
“all the suits care about is the bottom line”
a petition or appeal made to a person of superior status or rank
playing card in any of four sets of 13 cards in a pack; each set has its own symbol and color
“a flush is five cards in the same suit”
be agreeable or acceptable
“This time suits me”
Synonyms, antonyms and the broader and narrower relations for suit come from Princeton University’s WordNet. Full sources and licences.