rumbling

rumbling /ˈrʌmbəlɪŋ/ noun
plural rumblings
rumbling
/ˈrʌmbəlɪŋ/
noun
plural rumblings
Britannica Dictionary definition of RUMBLING
1 
[count] : a low, heavy, continuous sound or series of sounds — usually singular
2 
rumblings [plural] : written or spoken comments showing that people are unhappy about something