grumbling
adj. 喃喃鸣不平的；出怨言的
近义词：grumble，rumbling，rumble，muttering，murmuring，murmur，mutter，
英英释义
Noun
- a loud low dull continuous noise;
"they heard the rumbling of thunder"
- a complaint uttered in a low and indistinct tone
Adjective
- continuous full and low-pitched throbbing sound;
"the rumbling rolling sound of thunder"