cloudiness vs mistiness

cloudiness and mistiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
cloudiness	Yes	No	No	No
mistiness	Yes	No	No	No

As nouns, mistiness is a hyponym of cloudiness; that is, mistiness is a word with a more specific, narrower meaning than cloudiness:

Other hyponyms of cloudiness include turbidity, turbidness, haziness, steaminess, vaporousness, vapourousness.

cloudiness (noun)	mistiness (noun)
the quality of being cloudy	cloudiness resulting from haze or mist or vapor
the state of the sky when it is covered by clouds
gloomy semidarkness caused by cloud cover