bellyacher vs complainer

bellyacher and complainer both are nouns.

Word	Noun	Adjective	Verb	Adverb
bellyacher	Yes	No	No	No
complainer	Yes	No	No	No

As nouns, bellyacher and complainer are synonyms defined as:

bellyacher and complainer: a person given to excessive complaints and crying and whining

Other synonyms of bellyacher include crybaby, grumbler, moaner, sniveller, squawker, whiner.

bellyacher (noun)	complainer (noun)
a person given to excessive complaints and crying and whining	a person given to excessive complaints and crying and whining