impuissance vs powerlessness

impuissance and powerlessness both are nouns.

Word	Noun	Adjective	Verb	Adverb
impuissance	Yes	No	No	No
powerlessness	Yes	No	No	No

As nouns, powerlessness is a hypernym of impuissance; that is, powerlessness is a word with a broader meaning than impuissance:

impuissance: powerlessness revealed by an inability to act
powerlessness: the quality of lacking strength or power; being weak and feeble

Other hypernyms of impuissance include impotence, impotency.

impuissance (noun)	powerlessness (noun)
powerlessness revealed by an inability to act	the quality of lacking strength or power; being weak and feeble