to murmur or mutter in discontent; complain sullenly.

to utter low, indistinct sounds; growl.

to rumble

The thunder grumbled in the west.

to express or utter with murmuring or complaining.

an expression of discontent; complaint; unhappy murmur; growl.

grumbles, a grumbling, discontented mood.

a rumble.

verb

compliment , praise

verb

bellyache * , carp , find fault , fuss , gripe , groan , grouch * , grouse , kick , kvetch , moan , protest , pule , repine , scold , snivel * , squawk * , whine , bark , croak , gnarl , gnarr , growl , grunt , gurgle , mumble , mutter , roar , roll , snap , snarl , snuffle , splutter , murmur , boom , begrudge , bellyache , complain , crab , fret , grouch , rumble , squawk

noun

grunt , murmur