serve has 17 distinct synonyms spread across 11 of its 16 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.
devote (part of) one's life or efforts to, as of countries, institutions, or ideas
“She served the art of music”
promote, benefit, or be useful or beneficial to
“Art serves commerce”
do military service
“She served in Vietnam”
(sports) a stroke that puts the ball in play
“his powerful serves won the game”
Synonyms, antonyms and the broader and narrower relations for serve come from Princeton University’s WordNet. Full sources and licences.