killer, slayer

someone who causes the death of a person or animal

• executioner, public executioner — an official who inflicts capital punishment in pursuit of a warrant
• exterminator, terminator, eradicator — someone who exterminates (especially someone whose occupation is the extermination of troublesome rodents and insects)
• garroter, garrotter, strangler, throttler, choker — someone who kills by strangling
• murderer, liquidator, manslayer — a criminal who commits homicide (who performs the unlawful premeditated killing of another human being)
• poisoner — someone who kills with poison
• regicide — someone who commits regicide; the killer of a king
• suicide, felo-de-se — a person who kills himself intentionally

• person, individual, someone, somebody, mortal, human, soul — a human being