Main entry: grumble, grumbling, murmur, murmuring, mutter, muttering
Definition: a complaint uttered in a low and indistinct tone
Main entry: murmur, murmuration, murmuring, mussitation, mutter, muttering
Definition: a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
Main entry: susurrant, whispering, murmuring
Definition: making a low continuous indistinct sound
Usage: like murmuring waves; susurrant voices