mutterer vs mutter

mutterer and mutter both are nouns.

Word	Noun	Adjective	Verb	Adverb
mutterer	Yes	No	No	No
mutter	Yes	No	Yes	No

mutterer (noun)	mutter (noun)
a person who speaks softly and indistinctly	a complaint uttered in a low and indistinct tone
	a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech

mutterer (verb)	mutter (verb)
	make complaining remarks or noises under one's breath
	talk indistinctly; usually in a low voice