Slaughter, Wholesale/mass slaughter, Indiscriminate killing, Mass murder, Mass execution, Annihilation, Liquidation, Decimation, Extermination, Carnage, Butchery, Bloodbath, Bloodletting, Pogrom, Genocide, Ethnic cleansing, Holocaust, Night of the long knives, Slaying, Slaughter, Butcher, Murder, Kill, Annihilate, Exterminate, Execute, Liquidate, Eliminate, Decimate, Wipe out, Mow down, Cut down, Put to the sword, Put to death, Slay

(Noun : The savage and excessive killing of many people)
(Verb : Kill a large number of people indiscriminately)