improper vs incorrect

improper and incorrect both are adjectives.

Word	Noun	Adjective	Verb	Adverb
improper	No	Yes	No	No
incorrect	No	Yes	No	No

improper (adjective)	incorrect (adjective)
not suitable or right or appropriate	not correct; not in conformity with fact or truth
not appropriate for a purpose or occasion	not in accord with established usage or procedure
not conforming to legality, moral law, or social convention	characterized by errors; not agreeing with a model or not following established rules
	(of a word or expression) not agreeing with grammatical principles