complain vs bitch

complain is not a noun while bitch is a noun.

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

As verbs, bitch is a hyponym of complain; that is, bitch is a word with a more specific, narrower meaning than complain:

complain (noun)	bitch (noun)
	female of any member of the dog family
	informal terms for objecting
	a person (usually but not necessarily a woman) who is thoroughly disliked
	an unpleasant difficulty

complain (verb)	bitch (verb)
express complaints, discontent, displeasure, or unhappiness	say mean things
make a formal accusation; bring a formal charge	complain