impingement vs encroachment

impingement and encroachment both are nouns.

Word	Noun	Adjective	Verb	Adverb
impingement	Yes	No	No	No
encroachment	Yes	No	No	No

As nouns, impingement and encroachment are synonyms defined as:

Other synonyms of impingement include impact.

impingement (noun)	encroachment (noun)
influencing strongly	entry to another's property without right or permission
a sharp collision produced by striking or dashing against something	influencing strongly
	any entry into an area not previously occupied