Deep- and slow-sounding. His rumbling voice suited the solemn occasion.

Is rumbling a verb or adjective?

verb (used without object), rum·bled, rum·bling. to make a deep, heavy, somewhat muffled, continuous sound, as thunder. to move or travel with such a sound: The train rumbled on.

Is Rumble a noun or adjective?

As a noun, rumble can mean "a low sound," “a seat in the back of a carriage” (the rumble seat) or " a street fight." It's a little old fashioned today to call a gang brawl a rumble, but if you've ever seen the movie "West Side Story," you've seen the rumble between the Jets and the Sharks.