ineptness vs inept

ineptness is a noun but inept is not a noun.

Word	Noun	Adjective	Verb	Adverb
ineptness	Yes	No	No	No
inept	No	Yes	No	No

ineptness (noun)	inept (noun)
the quality of having the wrong properties for a specific purpose
unskillfulness resulting from a lack of training

ineptness (adjective)	inept (adjective)
	generally incompetent and ineffectual
	not elegant or graceful in expression
	revealing lack of perceptiveness or judgment or finesse