groundlessness vs ineptitude

groundlessness and ineptitude both are nouns.

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

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

Other hypernyms of groundlessness include worthlessness.

groundlessness (noun)	ineptitude (noun)
the quality of lacking substance or value	having no qualities that would render it valuable or useful
	unskillfulness resulting from a lack of training