murmur

Noun

• a complaint uttered in a low and indistinct tone

• an abnormal sound of the heart; sometimes a sign of abnormal function of the heart valves

• a schwa that is incidental to the pronunciation of a consonant

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

Verb

• make complaining remarks or noises under one's breath
  • she grumbles when she feels overworked
    

• speak softly or indistinctly
  • She murmured softly to the baby in her arms
    

Related words

• Synonyms: 
  grumble , grumbling , murmuring , mutter , muttering , heart murmur , cardiac murmur , murmur vowel , murmuration , mussitation , croak , gnarl