squawker vs grumbler

squawker and grumbler both are nouns.

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

As nouns, squawker and grumbler are synonyms defined as:

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

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

squawker (noun)	grumbler (noun)
the loudspeaker on an intercom or public address system	a person given to excessive complaints and crying and whining
a person given to excessive complaints and crying and whining