massacre

v. slaughter, kill a large number of people violently; defeat, destroy (Colloquial)

n. widespread slaughter (of people), bloodshed, extermination; total defeat (Colloquial)

Massacre most commonly refers to individual events of deliberate and direct mass killing where the victims have no reasonable means of defense and pose no immediate physical threat to the assailants. If performed by members of the military or other government agents during a time of war, the action may qualify as a war crime. The deliberate mass killing of prisoners of war or  civilians is often considered a massacre, however the term does not typically apply to the killing of armed combatants (except figuratively). Occasionally the term is also used to refer to the acts of a single individual rather than a group, such as the occasional labelling of school shootings as massacres. The term arose with the St. Bartholomew's Day massacre in France in 1572 and the word only acquired a general meaning latterly. In Guatemala, where massacres of Maya people were common during the Civil War, the Historical Clarification Commission agreed on a specific definition: "A massacre shall be considered the execution of five or more people, in the same place, as part of the same operation and whose victims were in an indefensible state." In Colombia, the term is applied to the murder of at least half a dozen or more at one time.
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Noun
1. the savage and excessive killing of many people
(synonym) slaughter, mass murder, carnage, butchery
(hypernym) murder, slaying, execution
(hyponym) bloodbath, bloodletting, bloodshed, battue
(derivation) slaughter, mow down
Verb
1. kill a large number of people indiscriminately; "The Hutus massacred the Tutsis in Rwanda"
(synonym) slaughter, mow down
(hypernym) kill
(derivation) slaughter, mass murder, carnage, butchery

n. slaughter, massacre, pogrom; killing, bloodshed, butchery, carnage

v. massacre, murder, butcher, slay

n. carnage; havoc; massacre, pogrom

v. slaughter, massacre