murmur

noun

1.
a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
murmuration murmuring mussitation mutter muttering
Derived from:
murmur murmurer murmurous
2.
a schwa that is incidental to the pronunciation of a consonant
murmur vowel
3.
an abnormal sound of the heart; sometimes a sign of abnormal function of the heart valves
cardiac murmur heart murmur
4.
a complaint uttered in a low and indistinct tone
grumble grumbling murmuring mutter muttering
Derived from:
murmur