emptiness vs ineptitude

emptiness and ineptitude both are nouns.

Word	Noun	Adjective	Verb	Adverb
emptiness	Yes	No	No	No
ineptitude	Yes	No	No	No

As nouns, ineptitude is a hypernym of emptiness; that is, ineptitude is a word with a broader meaning than emptiness:

Other hypernyms of emptiness include worthlessness.

emptiness (noun)	ineptitude (noun)
the quality of being valueless or futile	having no qualities that would render it valuable or useful
an empty area or space	unskillfulness resulting from a lack of training
the state of containing nothing
having an empty stomach