n a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
n a schwa that is incidental to the pronunciation of a consonant
n an abnormal sound of the heart; sometimes a sign of abnormal function of the heart valves
n a complaint uttered in a low and indistinct tone
v speak softly or indistinctly
v make complaining remarks or noises under one's breath
