clearness n. + Add to list US //ˈkɫɪɹnəs// UK //klˈiənəs// clear·ness Archaic SynonymsAntonymsEtymology Synonyms claritylimpidityluciditylucidnesspellucidityuncloudedness Antonyms obscurityopacityunclearnessOriginMEclernesse→ENclearness From Middle English clernesse; equivalent to clear + -ness.