toy has 8 distinct synonyms spread across 6 of its 8 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 nonfunctional replica of something else (frequently used as a modifier)
“a toy stove”
a device regarded as providing amusement
“private airplanes are a rich man's toy”
manipulate manually or in one's mind or imagination
“She played nervously with her wedding ring”
Synonyms, antonyms and the broader and narrower relations for toy come from Princeton University’s WordNet. Full sources and licences.