rumbling

(noun) a loud low dull continuous noise. Synonyms: rumble, grumble, grumbling. Example: "They heard the rumbling of thunder."

(verb) make a low noise. Synonyms: rumble, grumble. Example: "Rumbling thunder."

(verb) to utter or emit low dull rumbling sounds. Synonyms: grumble, growl, rumble. Examples: "He grumbled a rude response." "Stones grumbled down the cliff."

(adj) continuous full and low-pitched throbbing sound. Synonyms: grumbling. Example: "The rumbling rolling sound of thunder."