complain vs complaint

complain is not a noun while complaint is a noun.

Word	Noun	Adjective	Verb	Adverb
complain	No	No	Yes	No
complaint	Yes	No	No	No

complain (noun)	complaint (noun)
	an expression of grievance or resentment
	(formerly) a loud cry (or repeated cries) of pain or rage or sorrow
	(civil law) the first pleading of the plaintiff setting out the facts on which the claim for relief is based
	(criminal law) a pleading describing some wrong or offense
	an often persistent bodily disorder or disease; a cause for complaining

complain (verb)	complaint (verb)
express complaints, discontent, displeasure, or unhappiness
make a formal accusation; bring a formal charge