skipjack has 6 distinct synonyms spread across 3 of its 3 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.
oceanic schooling tuna of considerable value in Pacific but less in Atlantic; reaches 75 pounds; very similar to if not the same as oceanic bonito
medium-sized tuna-like food fish of warm Atlantic and Pacific waters; less valued than tuna
able to right itself when on its back by flipping into the air with a clicking sound
Synonyms, antonyms and the broader and narrower relations for skipjack come from Princeton University’s WordNet. Full sources and licences.