meaning of grumble
1. To murmur or mutter with discontent; to make ill-natured complaints in a low voice and a surly manner.
2. To growl; to snarl in deep tones; as, a lion grumbling over his prey.
3. To rumble; to make a low, harsh, and heavy sound; to mutter; as, the distant thunder grumbles.
4. To express or utter with grumbling.
5. The noise of one that grumbles.
6. A grumbling, discontented disposition.
7. a complaint uttered in a low and indistinct tone