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killer

/ˈkɪl.ər/
IELTSAcademic
noun
  1. 1.

    A person or animal that kills someone or something. It is often used for a murderer, or for an animal that hunts and kills other animals.

    • The police caught the killer.
    • Lions are natural killers.
  2. 2.

    Something very impressive, powerful, or very effective. In this use, it is informal.

    • That was a killer performance.
    • She gave a killer presentation.
adjective

Very difficult, severe, or exhausting. This use is informal.

  • It was a killer exam.
  • We had a killer day at work.

Adinary Nuance

Killer is stronger and more direct than murderer when talking about a person who kills. Murderer is the normal legal word, while killer can also sound general, dramatic, or informal. In everyday speech, killer often means “excellent” or “very hard,” which murderer never means.

In other languages

Vietnamese
kẻ giết người
Spanish
asesino
Chinese
杀手
Japanese
殺人者
Korean
살인자

Etymology

Killer comes from the verb kill, from Old English cyllan and related Germanic forms. The noun use became common in English for a person who kills, and the informal adjective use developed later.

Common phrases

killer instinctkiller whalekiller jobkiller performance

Synonyms

Related words

Frequently asked questions

Is killer a formal word?
The noun can be serious, but the adjective use is informal. In business or academic writing, avoid the slang meaning.
What is the difference between killer and murderer?
A murderer is a person who illegally kills someone. Killer is broader and can sound less legal and more general.
Can killer mean something good?
Yes. In informal speech, a killer idea or killer performance means very impressive.
How do I use killer in a sentence?
You can say, “The meal was killer,” or “Police found the killer.”