visibility vs clearness

visibility and clearness both are nouns.

Word	Noun	Adjective	Verb	Adverb
visibility	Yes	No	No	No
clearness	Yes	No	No	No

As nouns, clearness is a hypernym of visibility; that is, clearness is a word with a broader meaning than visibility:

Other hypernyms of visibility include clarity, uncloudedness.

visibility (noun)	clearness (noun)
quality or fact or degree of being visible; perceptible by the eye or obvious to the eye	free from obscurity and easy to understand; the comprehensibility of clear expression
capability of providing a clear unobstructed view	the quality of clear water
degree of exposure to public notice