unworthiness vs unsuitability

unworthiness and unsuitability both are nouns.

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

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

unworthiness: the quality of being not particularly suitable or befitting
unsuitability: the quality of having the wrong properties for a specific purpose

Other hypernyms of unworthiness include ineptness, unsuitableness.

unworthiness (noun)	unsuitability (noun)
the quality or state of lacking merit or value	the quality of having the wrong properties for a specific purpose
the quality of being not particularly suitable or befitting