scup has 7 distinct synonyms spread across 3 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.
flesh of fish found in colder waters of northern Atlantic coast of the United States
lean flesh of fish found in warm waters of southern Atlantic coast of the United States
porgy of southern Atlantic coastal waters of North America
found in Atlantic coastal waters of North America from South Carolina to Maine; esteemed as a panfish
Synonyms, antonyms and the broader and narrower relations for scup come from Princeton University’s WordNet. Full sources and licences.