hum vs sigh

hum

verb
  • To express by humming. 

  • To produce low sounds which blend continuously 

  • 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 

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

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

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. 

sigh

verb
  • To express by sighs; to utter in or with sighs. 

  • To inhale a larger quantity of air than usual, and immediately expel it; to make a deep single audible respiration, especially as the result or involuntary expression of fatigue, exhaustion, grief, sorrow, frustration, or the like. 

  • To utter sighs over; to lament or mourn over. 

  • To exhale (the breath) in sighs. 

  • To lament; to grieve. 

  • To make a sound like sighing. 

noun
  • A person who is bored. 

  • A deep, prolonged audible inhale and exhale of breath; as when fatigued, frustrated, grieved, or relieved; the act of sighing. 

  • a manifestation of grief; a lament. 

intj
  • An expression of fatigue, exhaustion, grief, sorrow, frustration, or the like, often used in casual written contexts. 

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