impinging vs impact

impinging and impact both are nouns.

Word	Noun	Adjective	Verb	Adverb
impinging	Yes	No	No	No
impact	Yes	No	Yes	No

As nouns, impact is a hyponym of impinging; that is, impact is a word with a more specific, narrower meaning than impinging:

Other hyponyms of impinging include collision, hit, engagement, interlocking, mesh, meshing, flick, touch, touching.

impinging (noun)	impact (noun)
the physical coming together of two or more things	influencing strongly
	the violent interaction of individuals or groups entering into combat
	the striking of one body against another
	a forceful consequence; a strong effect

impinging (verb)	impact (verb)
	have an effect upon
	press or wedge together; pack together