ineffectualness vs impotency

ineffectualness and impotency both are nouns.

Word	Noun	Adjective	Verb	Adverb
ineffectualness	Yes	No	No	No
impotency	Yes	No	No	No

As nouns, impotency is a hypernym of ineffectualness; that is, impotency is a word with a broader meaning than ineffectualness:

Other hypernyms of ineffectualness include impotence, powerlessness.

ineffectualness (noun)	impotency (noun)
lacking the power to be effective	the quality of lacking strength or power; being weak and feeble
	an inability (usually of the male animal) to copulate