pike has 7 distinct synonyms spread across 1 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 broad highway designed for high-speed traffic
highly valued northern freshwater fish with lean flesh
a sharp point (as on the end of a spear)
any of several elongate long-snouted freshwater game and food fishes widely distributed in cooler parts of the northern hemisphere
Synonyms, antonyms and the broader and narrower relations for pike come from Princeton University’s WordNet. Full sources and licences.