S: (v) grouch, grumble, scold (show one's unhappiness or critical attitude) "He scolded about anything that he thought was wrong"; "We grumbled about the increased work load"
S: (v) murmur, mutter, grumble, croak, gnarl (make complaining remarks or noises under one's breath) "she grumbles when she feels overworked"
S: (v) grumble, growl, rumble (to utter or emit low dull rumbling sounds) "he grumbled a rude response"; "Stones grumbled down the cliff"
S: (v) rumble, grumble (make a low noise) "rumbling thunder"