inhibit has 2 distinct synonyms spread across 1 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.
prohibit, forbid, or prevent from doing something
“Contact between the young was inhibited by strict social customs”
limit, block, or decrease the action or function of
“inhibit the action of the enzyme”
Synonyms, antonyms and the broader and narrower relations for inhibit come from Princeton University’s WordNet. Full sources and licences.
consciously restrain from showing; of emotions, desires, impulses, or behavior
“suppress a smile”
make (someone) self-conscious and as a result unable to act naturally
“his father's cold and distant demeanor inhibited him emotionally”