ɡɹaʊl ɡɹaʊl ˈɡɹʌmbl̩ ˈɡɹʌmbl̩ ˈɹʌmb(ə)l ˈɹʌmb(ə)l to utter or emit low dull rumbling sounds he grumbled a rude response Stones grumbled down the cliff a fight between rival gangs of adolescents make a low noise rumbling thunder a servant's seat (or luggage compartment) in the rear of a carriage a loud low dull continuous noise they heard the rumbling of thunder