- [noun] a loud low dull continuous noise; "they heard the rumbling of thunder"
Synonyms: rumble, rumbling, grumbling
- [noun] a complaint uttered in a low and indistinct tone
Synonyms: grumbling, murmur, murmuring, mutter, muttering
- [verb] show one's unhappiness or critical attitude; "He scolded about anything that he thought was wrong"; "We grumbled about the increased work load"
Synonyms: grouch, scold
- [verb] make complaining remarks or noises under one's breath; "she grumbles when she feels overworked"
Synonyms: murmur, mutter, croak, gnarl
- [verb] to utter or emit low dull rumbling sounds; "he grumbled a rude response"; "Stones grumbled down the cliff"
Synonyms: growl, rumble
- [verb] make a low noise; "rumbling thunder"