dragon has 5 distinct synonyms spread across 4 of its 4 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 creature of Teutonic mythology; usually represented as breathing fire and having a reptilian body and sometimes wings
a fiercely vigilant and unpleasant woman
Synonyms, antonyms and the broader and narrower relations for dragon come from Princeton University’s WordNet. Full sources and licences.
a faint constellation twisting around the north celestial pole and lying between Ursa Major and Cepheus
any of several small tropical Asian lizards capable of gliding by spreading winglike membranes on each side of the body