murmuring

A continuous murmur; a low confused noise.

Making or consisting in a low continuous noise.

Uttering complaints in a low voice or sullen manner; grumbling; complaining: as, a person of a murmuring disposition.

Uttering murmurs; making low sounds; complaining.

Present participle of murmur.

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

making a low continuous indistinct sound

a complaint uttered in a low and indistinct tone