1. Make a low continuous sound
   "The refrigerator is humming"
    
2. Sing with closed lips
   "She hummed a melody"
    
3. Sound with a monotonous hum
   "The air conditioner hummed all night";
   - thrum
    
4. Be noisy with activity
   "This office is humming with activity";
   - buzz, seethe
    
5. [Brit, informal] Smell badly and offensively
   "The garbage was humming in the summer heat";
   - reek, stink

1. A humming noise
   "the hum of distant traffic";
   - humming
    
2. The state of being or appearing to be actively engaged in an activity
   "there is a constant hum of military preparation";
   - busyness

1. Exclamation expressing doubt, deliberation, dissent, or hesitation
   - ahem, hmm, h'm

1. An Islamic fundamentalist group in Pakistan that fought the Soviet Union in Afghanistan in the 1980s; now operates as a terrorist organization primarily in Kashmir and seeks Kashmir's accession by Pakistan
   - Harkat-ul-Mujahideen, Harkat-ul-Mujahidin, Harkat ul-Ansar, HUA, Harkat ul-Mujahedeen, Al Faran, Movement of Holy Warriors

Derived forms: hums, hummed, humming

Type of: action, activeness, activity, foreign terrorist organisation [Brit], foreign terrorist organization, FTO, go, make noise, noise, resound, sing, smell, sound, terrorist group, terrorist organisation [Brit], terrorist organization

Encyclopedia: Hum, Nicholas