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English definition of “killer”

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killer

noun [C]  /ˈkɪl·ər/ us  
someone or something that causes someone or something to die: The police haven’t found the killer yet. Heart disease is a killer (= cause of death). infml If something is described as a killer, it is very difficult: The test was a real killer. infml A killer is also someone or something that is very entertaining or skilled: Dizzy was a killer on the trumpet.
(Definition of killer from the Cambridge Academic Content Dictionary © Cambridge University Press)
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