Killer (Swiss band), a 1980s heavy metal band

"Killer", or "Kira", nickname of Light Yagami, the main character of the Japanese manga Death Note

"The Killer", a nickname for singer/pianist Jerry Lee Lewis

Killer (film), a 1994 film featuring Peter Boyle

Killer (Tech N9ne album), a forthcoming album by Tech N9ne

Assassin (game), or Killer, a live-action role-playing game

"Killer", the nickname of baseball player Harmon Killebrew

"Killer", a song by Pat Travers

The Killer (1989 film), directed by John Woo and starring Chow Yun Fat

"Killer" (Adamski song), a song by Adamski and Seal

"Killer", postal jargon for a cancellation

Killer (card game), a climbing card game related to Tien len

"Killer", a song by the Tiger Lillies

Killer (British band), a 1980s psychobilly band

Killer (1991 film), a Telugu film starring Akkineni Nagarjuna

The Killer (Impious album), an album by Impious

"Killer" (CSI), an episode of the American television series CSI: Crime Scene Investigation

Killer (album), an album by Alice Cooper

"Killer" (Kiss song), a song by Kiss

"Killer", a song by Van Der Graaf Generator from H to He, Who Am the Only One

Killer: A Journal of Murder, a 1996 film about serial killer Carl Panzram

The Killer (2006 film), a Bollywood film starring Emraan Hashmi and Irrfan Khan

The Killer, English title of Tueur sans gages, a play by Eugène Ionesco

Killer (computer), or The Killer, was the name of an AT&T public-access UNIX machine involved in Operation Sundevil

Killer (Finnish band), an early 2000s Finnish pop band

Killer (pool), a multi-player pocket billiards (pool) game

Killer: Dead or Alive, a 2006 thriller film

Killer: A Journal of Murder (novel), a 1970 biographical novel upon which the 1996 film is based

"Killer", a song by Boy Kill Boy from Civilian

Kiler, a 1997 Polish film

A killer is a person (such as a serial killer or assassin, or a murderer more generally) that kills.