hangman — a person who hangs criminals who are condemned to death; public executioner.
firing squad — a military detachment assigned to execute a condemned person by shooting.
electrocutioner — A person who carries out an execution by means of electricity.
garroter — a method of capital punishment of Spanish origin in which an iron collar is tightened around a condemned person's neck until death occurs by strangulation or by injury to the spinal column at the base of the brain.
strangler — to kill by squeezing the throat in order to compress the windpipe and prevent the intake of air, as with the hands or a tightly drawn cord.
death squad — Death squads are groups of people who operate illegally and carry out the killing of people such as their political opponents or criminals.
hired gun — a person hired to kill someone, as a gunfighter or professional killer.
hit man — a hired killer, especially a professional killer from the underworld.
lyncher — to put to death, especially by hanging, by mob action and without legal authority.
