American English

Definition of deadly adjective from the Oxford Advanced American Dictionary

     

    deadly

     adjective
    adjective
    NAmE//ˈdɛdli//
     
    (deadlier, deadliest)
     
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  1. 1More deadly and deadliest are the usual forms. You can also use most deadly. causing or likely to cause death synonym lethal a deadly weapon/disease deadly poison The cobra is one of the world's deadliest snakes. The terrorists have chosen to play a deadly game with the civilian population.
  2. 2 [only before noun] extreme; complete We sat in deadly silence. They are deadly enemies (= are full of hatred for each other).
  3. 3extremely effective, so that no defense is possible His aim is deadly (= so accurate that he can kill easily). Snipers can shoot with deadly accuracy.
  4. 4(informal) very boring The lecture was absolutely deadly.
See the Oxford Advanced Learner's Dictionary entry: deadly