Definition

1. Noun:
   • A person or thing that kills: A "killer" is someone who causes the death of a person or animal, or a thing that is the cause of death.
   • A very difficult or formidable thing: Informally, a "killer" can refer to something that is extremely difficult to deal with or overcome.
   • A predatory black-and-white toothed whale: In zoology, "killer" is short for "killer whale," a large marine mammal.

Usage Examples

• Noun (Person/Agent):
  • The police are searching for the killer. (The police are searching for the person who caused the death.)
  • Heart disease remains the leading killer in many developed nations. (Heart disease is the primary cause of death.)
• Noun (Difficult Thing):
  • That final hill on the bike route is a real killer. (That final hill is extremely challenging.)
  • The project deadline is a killer; I have to work all weekend. (The deadline is very demanding.)
• Noun (Animal):
  • We saw a pod of killers, or orcas, off the coast. (We saw a group of killer whales.)

Advanced Usage

• "Killer instinct": A ruthless determination to succeed or win.
  • To be a champion in boxing, you need a killer instinct.
• "Killer app": In computing, an application that is so useful or desirable that it drives the adoption of the technology it runs on.
  • The spreadsheet was the killer app for early personal computers.
• "Killer whale": The full term for the marine mammal .
  • Killer whales are actually the largest species of dolphin.

Variants and Related Words

• Kill (verb): To cause the death of.
  • The frost will kill the plants.
• Killing (noun/adjective):
  • Noun: An act of causing death.

    • The killing was ruled a homicide.
  • Adjective: Extremely funny or exhausting.

    • He told a killing joke. / I just finished a killing workout.

Synonyms

• Murderer: A person who commits murder (specifically for a person who kills unlawfully).
• Assassin: A murderer, often one who kills a prominent figure.
• Slayer: A person who kills someone (can be formal or literary).
• Cause of death: The specific injury or disease that leads to death.

Related Phrases

• Lady-killer: (Informal, dated) A man who is very attractive to women.
  • In his youth, he was quite the lady-killer.
• Killer blow/strike: A decisive action that ends a contest or effort.
  • The boxer landed a killer blow in the third round.

Idioms

• To be a killer: To be extremely good, impressive, or effective (often used positively in informal contexts).
  • Her performance last night was a killer! (Her performance was excellent.)
• Dressed to kill: Wearing very attractive or stylish clothes intended to impress.
  • She arrived at the party dressed to kill.

Noun

1. predatory black-and-white toothed whale with large dorsal fin; common in cold seas
2. a difficulty that is hard to deal with
   • that exam was a real killer
3. the causal agent resulting in death
   • heart disease is the biggest killer in the United States
4. someone who causes the death of a person or animal