chicken has 10 distinct synonyms spread across 4 of its 5 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 domestic fowl bred for flesh or eggs; believed to have been developed from the red jungle fowl
a foolhardy competition; a dangerous activity that is continued until one competitor becomes afraid and stops
easily frightened
Synonyms, antonyms and the broader and narrower relations for chicken come from Princeton University’s WordNet. Full sources and licences.