inconvenience vs ineptness

inconvenience and ineptness both are nouns.

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

As nouns, ineptness is a hypernym of inconvenience; that is, ineptness is a word with a broader meaning than inconvenience:

inconvenience: the quality of not being useful or convenient
ineptness: the quality of having the wrong properties for a specific purpose

Other hypernyms of inconvenience include unsuitability, unsuitableness.

inconvenience (noun)	ineptness (noun)
the quality of not being useful or convenient	the quality of having the wrong properties for a specific purpose
a difficulty that causes anxiety	unskillfulness resulting from a lack of training
an inconvenient discomfort

inconvenience (verb)	ineptness (verb)
to cause inconvenience or discomfort to