What is the meaning of murmuring?

noun

• A low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech.
  • synonyms: mutter, muttering, murmur, murmuration, mussitation
• A complaint uttered in a low and indistinct tone.
  • synonyms: grumble, grumbling, murmur, mutter, muttering

verb

• Speak softly or indistinctly.
  • usage: "She murmured softly to the baby in her arms"
  • synonyms: murmur
• Make complaining remarks or noises under one's breath.
  • usage: "she grumbles when she feels overworked"
  • synonyms: murmur, mutter, grumble, croak, gnarl

adjective

• Making a low continuous indistinct sound.
  • usage: "like murmuring waves"; "susurrant voices"
  • synonyms: susurrant, whispering