stormy has 1 distinct synonym spread across 1 of its 2 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. Its one recorded opposite is calm.
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.
(especially of weather) affected or characterized by storms or commotion
“a stormy day”
Synonyms, antonyms and the broader and narrower relations for stormy come from Princeton University’s WordNet. Full sources and licences.