Noah Webster
Mutter
MUT'TER, verb intransitive [Latin mutio, muttio, and musso, mussito; allied perhaps to muse, which see.]
1. To utter words with a low voice and compressed lips, with sullenness or in complaint; to grumble; to murmur.
Meantime your filthy foreigner will stare,
And mutter to himself.
2. To sound with a low rumbling noise.
Thick lightnings flash, the muttering thunder rolls.
MUT'TER, verb transitive To utter with imperfect articulations, or with a low murmuring voice.
Your lips have spoken lies, your tongue hath muttered perverseness. Isaiah 59:3.
They in sleep will mutter their affairs.
MUT'TER, noun Murmur; obscure utterance.