inconsistency has 3 distinct synonyms spread across 1 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. Its one recorded opposite is consistency.
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 relation between propositions that cannot both be true at the same time
the quality of being inconsistent and lacking a harmonious uniformity among things or parts
Synonyms, antonyms and the broader and narrower relations for inconsistency come from Princeton University’s WordNet. Full sources and licences.