unbecomingness vs unsuitability

unbecomingness and unsuitability both are nouns.

Word	Noun	Adjective	Verb	Adverb
unbecomingness	Yes	No	No	No
unsuitability	Yes	No	No	No

As nouns, unsuitability is a hypernym of unbecomingness; that is, unsuitability is a word with a broader meaning than unbecomingness:

unbecomingness: The state of not being flattering, attractive or appropriate.
unsuitability: the quality of having the wrong properties for a specific purpose

Other hypernyms of unbecomingness include appearance, visual aspect, ineptness, unsuitableness.

unbecomingness (noun)	unsuitability (noun)
the quality of being unbecoming	the quality of having the wrong properties for a specific purpose
The state of not being flattering, attractive or appropriate.