adapt has 3 distinct synonyms spread across 2 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. 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.
make fit for, or change to suit a new purpose
“Adapt our native cuisine to the available food resources of the new country”
adapt or conform oneself to new or different conditions
“We must adjust to the bad economic situation”
Synonyms, antonyms and the broader and narrower relations for adapt come from Princeton University’s WordNet. Full sources and licences.