grumbling
1. [ noun ] a loud low dull continuous noise
Synonyms: rumble grumble rumbling
Examples:

"they heard the rumbling of thunder"

Related terms: noise borborygmus grumble rumble
2. [ noun ] a complaint uttered in a low and indistinct tone
Synonyms: murmur murmuring mutter muttering grumble
Related terms: complaint murmur
3. [ adjective ] continuous full and low-pitched throbbing sound
Synonyms: rumbling
Examples:

"the rumbling rolling sound of thunder"

Related terms: full
4. [ adjective ] muttering discontentedly
Examples:

"the grumbling boarders requested a meeting with the cook"

Related terms: complaining
Similar spelling:   grumble
  Grumbles
  grumbler
  grumpiness
  green-blind