muttering
1. [ noun ] a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
Synonyms: murmur murmuring murmuration mussitation mutter
Related terms: sound mumble murmur
2. [ adjective ] speaking low and indistinctly
Synonyms: mumbling
Examples:

"a mumbling parson stood beside the dying man" "muttering crowds of onlookers"

Related terms: speaking
3. [ noun ] a complaint uttered in a low and indistinct tone
Synonyms: grumbling murmuring murmur mutter grumble
Related terms: complaint murmur
Similar spelling:   Mattern