impeach vs impeachment

impeach is not a noun while impeachment is a noun.

Word	Noun	Adjective	Verb	Adverb
impeach	No	No	Yes	No
impeachment	Yes	No	No	No

impeach (noun)	impeachment (noun)
	a formal document charging a public official with misconduct in office

impeach (verb)	impeachment (verb)
bring an accusation against; level a charge against
charge (a public official) with an offense or misdemeanor committed while in office
challenge the honesty or veracity of