adaptation has 3 distinct synonyms spread across 2 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.
a written work (as a novel) that has been recast in a new form
“the play is an adaptation of a short novel”
the process of adapting to something (such as environmental conditions)
Synonyms, antonyms and the broader and narrower relations for adaptation come from Princeton University’s WordNet. Full sources and licences.
(physiology) the responsive adjustment of a sense organ (as the eye) to varying conditions (as of light)