helplessness vs impuissance

helplessness and impuissance both are nouns.

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

As nouns, helplessness and impuissance are synonyms defined as:

helplessness and impuissance: powerlessness revealed by an inability to act

Other synonyms of helplessness include weakness.

helplessness (noun)	impuissance (noun)
powerlessness revealed by an inability to act	powerlessness revealed by an inability to act
a feeling of being unable to manage
the state of needing help from something