clearness has 6 distinct synonyms spread across 2 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 unclearness.
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.
free from obscurity and easy to understand; the comprehensibility of clear expression
Synonyms, antonyms and the broader and narrower relations for clearness come from Princeton University’s WordNet. Full sources and licences.
the quality of clear water
“when she awoke the clarity was back in her eyes”