adj 1: muttering discontentedly; "the grumbling boarders requested
a meeting with the cook"
2: continuous full and low-pitched throbbing sound; "the
rumbling rolling sound of thunder" [syn: rumbling]
n 1: a loud low dull continuous noise; "they heard the rumbling
of thunder" [syn: rumble, rumbling, grumble]
2: a complaint uttered in a low and indistinct tone [syn: grumble, murmur, murmuring, mutter, muttering]