negativity has 3 distinct synonyms spread across 4 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. Its one recorded opposite is positivity.
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.
the character of the negative electric pole
characterized by habitual skepticism and a disagreeable tendency to deny or oppose or resist suggestions or commands
Synonyms, antonyms and the broader and narrower relations for negativity come from Princeton University’s WordNet. Full sources and licences.
(chemistry) the tendency of an atom or radical to attract electrons in the formation of an ionic bond