Definitions

1. verb

to complain or express discontent in a low, gruff voice; to mutter or speak indistinctly.

“My son has been grumbling about his homework all evening.”

2. noun

a low, gruff sound, especially of discontent or annoyance.

“The grumble of thunder filled the darkening sky.”

3. noun

a complaint or expression of discontent.

“His constant grumble about the weather was starting to annoy me.”

4. verb

to make a low, gruff sound, especially of discontent or annoyance.

“The old engine started to grumble as the driver turned the key.”