grum·ble 
/ˈgrʌmbəl/ verb
grum·bles; grum·bled; grum·bling /ˈgrʌmbəl/ verb 1 : to complain quietly about something : to talk in an unhappy way [no obj] ▪ There's been a lot of grumbling among the employees. ▪ Some of the customers have been grumbling about poor service. ▪ Fans grumbled about the team's poor play. [+ obj] ▪ “When are we going to leave?” he grumbled. 2 [no obj] : to make a low, heavy sound : rumble
▪ His stomach was grumbling. ▪ We could hear thunder grumbling in the distance.
▪ His stomach was grumbling. ▪ We could hear thunder grumbling in the distance.
— grumble noun, plural grumbles [count]
▪ We could hear the grumble of thunder in the distance.
▪ We could hear the grumble of thunder in the distance.
— grum·bler /ˈgrʌmbəlɚ/ noun, plural grum·blers [count]
▪ He tries to ignore the grumblers and just do his job.
/ˈgrʌmbəlɚ/ noun, plural grum·blers [count] ▪ He tries to ignore the grumblers and just do his job.
— grum·bling noun, plural grum·blings [count, noncount]
▪ Your grumbling needs to stop.
▪ Your grumbling needs to stop.
