murmuring - noun

a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech

a complaint uttered in a low and indistinct tone

murmuring - adjective

• making a low continuous indistinct sound

murmuring - thesaurus

grumble   grumbling   murmur   murmuration   mussitation   mutter   muttering   susurrant   whispering