To whinge, moan, complain.
To make elaborate unnatural and distorted faces as a form of amusement or in a girning competition.
To grimace; to snarl.
A vocalization similar to a cat's purring.
To say (something) indistinctly, to mutter.
To speak or make low, indistinguishable noise; to mumble, mutter.
The sound made by any condition which produces noisy, or turbulent, flow of blood through the heart.
A muttered complaint or protest; the expression of dissatisfaction in a low muttering voice; any expression of complaint or discontent.
Soft indistinct speech.
Any low, indistinct sound, like that of running water.