distinctness has 5 distinct synonyms spread across 3 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. Its one recorded opposite is indistinctness.
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 quality of being sharp and clear
the state of being several and distinct
the quality of being not alike; being distinct or different from that otherwise experienced or known
Synonyms, antonyms and the broader and narrower relations for distinctness come from Princeton University’s WordNet. Full sources and licences.