coca has 3 distinct synonyms spread across 2 of its 3 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 South American shrub whose leaves are chewed by natives of the Andes; a source of cocaine
United States comedienne who starred in early television shows with Sid Caesar (1908-2001)
dried leaves of the coca plant (and related plants that also contain cocaine); chewed by Andean people for their stimulating effect
Synonyms, antonyms and the broader and narrower relations for coca come from Princeton University’s WordNet. Full sources and licences.