murderer

American  

[mur-der-er] / ˈmɜr dər ər /

noun

1. a person who commits murder.

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idioms

1. murderers' row,

   1. the row of cells in a prison where murderers and other violent or hard-core criminals are held.

   2. Baseball. a succession of heavy hitters scheduled to bat one after the other.

   3. any group of notorious or important people.

      a murderers' row of talent;

      a murderers' row of philosophers.

Other Word Forms

• self-murderer noun

Etymology

Origin of murderer

1300–50; Middle English mortherer, mord ( e ) rer; murder, -er ¹

Explanation

If you’re looking for a roommate and someone writes murderer under “occupation,” you should definitely keep looking. A murderer is a person who kills deliberately and without justification. In some instances, killing a person is considered a just or valid action — in a war, a soldier who kills another soldier is not considered to be a murderer, and people who kill in self-defense, to save themselves, are also not murderers. Killing out of anger or for money or revenge is murder, and anyone who does it is a murderer. Charles Manson is in jail for being a murderer. The Old English root of murderer is morðor, "unlawful killing."

Example Sentences

He joked the comments made him look like a real murderer, and said: "People who don't know I was in The Traitors must think I'm a serial killer."

From BBC • Jan. 30, 2026

The book does advance one theory of who the murderer is.

From Los Angeles Times • Jan. 26, 2026

Dupie, a convicted murderer, is in a relationship with a niece of opposition leader Sandra Torres, a former first lady who has fought and lost the last three presidential elections.

From Barron's • Jan. 23, 2026

The tag was also, incidentally, a play on “The Blue Dahlia,” a 1946 movie written by Raymond Chandler and starring Veronica Lake as a plucky drifter who helps the hero track down his wife’s murderer.

From The Wall Street Journal • Jan. 23, 2026

But I said that it wasn’t a proper book because it didn’t have a proper ending because I never found out who killed Wellington so the murderer was still At Large.

From "The Curious Incident of the Dog in the Night-Time" by Mark Haddon

Related Words

• assassin
• executioner