·noun Repressed or obscure utterance.
II. Mutter ·vi To sound with a low, rumbling noise.
III. Mutter ·vt To utter with imperfect articulations, or with a low voice; as, to mutter threats.
IV. Mutter ·vi To utter words indistinctly or with a low voice and lips partly closed; ·esp., to utter indistinct complaints or angry expressions; to Grumble; to Growl.