rumbling
rum-bling
adjective
Producing or characterised by a deep, continuous, low, resonant sound.
"A rumbling lorry drove past the house."
verb
Making a deep, continuous, low sound, often indistinct or threatening.
"The distant thunder was rumbling loudly."
noun
A deep, continuous, low sound, often indistinct or threatening.
"We heard a strange rumbling from downstairs."