Grumble

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