(Latin > French: wholesale slaughter, carnage; slaughterhouse, butchery)

massacre (s) (noun), massacres (pl)
1. The wholesale, pitiless slaughter of people or animals.
2. The savage killing of a considerable number of human beings under circumstances of atrocity or cruelty, or contrary to the acceptance of civilized people.
3. Slaughter or the killing of a large number of people or animals.
4. Etymology: from Middle French massacre, "wholesale slaughter, carnage", from Old French macacre, macecle, "slaughterhouse, butchery"; perhaps from Latin macellum, "provisions store, butcher shop".
massacre (verb), massacres; massacred; massacring
1. To kill thoughtlessly or without concern and an undisciplined way; to slaughter.
2. Informally, to defeat decisively or handle something badly: "Andrew massacred the German language as he tried to explain what happened."
massacred (adjective)
A reference to having killed a large number of people; especially, people who were not involved in any fighting or have no way of defending themselves: "The stories of the massacred people in Syria have been in the news for too long!"
massacrer (s) (noun), massacrers (0l)
1. Someone who kills indiscriminately, a large number of human beings or animals, as in barbarous warfare or persecution or for revenge or plunder.
2. Anyone who kills unnecessarily and without concern; especially, a large number of people.