sensitivity has 3 distinct synonyms spread across 5 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. Its one recorded opposite is insensitivity.
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.
(physiology) responsiveness to external stimuli; the faculty of sensation
“sensitivity to pain”
Synonyms, antonyms and the broader and narrower relations for sensitivity come from Princeton University’s WordNet. Full sources and licences.
the ability to respond to physical stimuli or to register small physical amounts or differences
“a galvanometer of extreme sensitivity”
the ability to respond to affective changes in your interpersonal environment