incorrect vs improper

incorrect and improper both are adjectives.

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

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