from The American Heritage® Dictionary of the English Language, 4th Edition
- intransitive v. To speak indistinctly in low tones.
- intransitive v. To complain or grumble morosely.
- transitive v. To utter or say in low indistinct tones.
- n. A low grumble or indistinct utterance.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A repressed or obscure utterance; an instance of muttering.
- n. peas
- v. To utter words, especially complaints or angry expressions, indistinctly or with a low voice and lips partly closed; to say under one's breath.
- v. To speak softly and incoherently, or with imperfect articulations.
- v. To make a sound with a low, rumbling noise.
from the GNU version of the Collaborative International Dictionary of English
- intransitive v. 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.
- intransitive v. To sound with a low, rumbling noise.
- transitive v. To utter with imperfect articulations, or with a low voice.
- n. Repressed or obscure utterance.
from The Century Dictionary and Cyclopedia
- To utter words in a low tone and with compressed lips, as in complaint or sullenness; murmur; grumble.
- To emit a low rumbling sound.
- To utter with imperfect articulation, or in a low murmuring tone.
- n. A murmur or murmuring; sullen or veiled utterance.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- v. talk indistinctly; usually in a low voice
- n. a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
- n. a complaint uttered in a low and indistinct tone
- v. make complaining remarks or noises under one's breath
Middle English muttren, possibly from Latin muttīre.(American Heritage® Dictionary of the English Language, Fourth Edition)