grumble

verb

• 1 [reporting verb] complain about something in a bad-tempered way: [with direct speech]:‘I’m getting old,’ she grumbled [no object]:the cashier grumbled about changing Swiss money [with clause]:his father was grumbling that he hadn’t heard from him

• 2 [no object] make a low rumbling sound:thunder was grumbling somewhere in the distance

• 3 [no object] (usually as adjective grumbling) (of an internal organ) give intermittent discomfort:a grumbling appendix

noun

• 1a complaint:the main grumble is that he spends too much time away

• 2a low rumbling sound.