mussitate vs mutter

mussitate is not a noun while mutter is a noun.

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

As verbs, mussitate and mutter are synonyms defined as:

Other synonyms of mussitate include maunder, mumble.

mussitate (noun)	mutter (noun)
	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

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