bellyacher vs grumbler

bellyacher and grumbler both are nouns.

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

As nouns, bellyacher and grumbler are synonyms defined as:

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

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

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