hum vs rumble

hum

verb
  • To produce low sounds which blend continuously 

  • To express by humming. 

  • To reek, smell bad. 

  • To make a sound from the vocal chords without pronouncing any real words, with one's lips closed. 

  • To drone like certain insects naturally do in motion, or sounding similarly 

  • To buzz, be busily active like a beehive 

noun
  • Unpleasant odour. 

  • A phenomenon, or collection of phenomena, involving widespread reports of a persistent and invasive low-frequency humming, rumbling, or droning noise not audible to all people. 

  • Busy activity, like the buzz of a beehive. 

  • A hummed tune, i.e. created orally with lips closed. 

  • An often indistinct sound resembling human humming. 

intj
  • Synonym of um: a noise indicating doubt, uncertainty, &c. 

  • Synonym of hmm: a noise indicating thought, consideration, &c. 

rumble

verb
  • To make a low, heavy, continuous sound. 

  • To move while making a rumbling noise. 

  • To fight; to brawl. 

  • to provide haptic feedback by vibrating. 

  • To cause to pass through a rumble, or polishing machine. 

  • To discover deceitful or underhanded behaviour. 

intj
  • An onomatopoeia describing a rumbling noise 

noun
  • A street fight or brawl. 

  • A rotating cask or box in which small articles are smoothed or polished by friction against each other. 

  • A low, heavy, continuous sound, such as that of thunder or a hungry stomach. 

How often have the words hum and rumble occurred in a corpus of books? (source: Google Ngram Viewer )