unsuitability vs unsuitable

unsuitability is a noun but unsuitable is not a noun.

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

unsuitability (noun)	unsuitable (noun)
the quality of having the wrong properties for a specific purpose

unsuitability (adjective)	unsuitable (adjective)
	not conducive to good moral development
	not worthy of being chosen (especially as a spouse)
	not meant or adapted for a particular purpose
	not capable of being applied