Synonyms for Slaughter:

n.

knock out, thrash, beat, crush, smash, overcome, win, overpower, defeat. euthanasia, fratricide, genocide, HIT, contract, culpable homicide, foul play. tear someone/something to pieces/shreds, tell off, attack, castigate, tear apart, harangue, take/bring/hold someone to task, savage, censure. cull, hunt, poach, put down, bag, hunt out, destroy. butchery (noun)
bloodletting, study at carnage.
defeat (noun)
drubbing.
killing (noun)
elimination, butchering, execution, hanging, asphyxiation, massacre, carnage, removal, manslaughter, assassination, liquidation, Snuffing, purging, bloodbath, Dispatching, bloodshed, slaying, extermination, strangulation.
slaughter (noun)
drubbing, debacle, butcher, mow down, thrashing, massacre, whipping, trouncing, carnage, walloping, mass murder.

v.

kill (verb)
dispatch, do away with, asphyxiate, strangle, snuff, suffocate, chill, crush, hang, smother, exterminate, defeat, butcher, liquidate, do in, eliminate, purge, put to sleep, sacrifice, thrash, assassinate, remove, ice, slay, massacre, drown, execute, destroy, smite.

Other synonyms:

bloodletting, bloodbath, bump off. bloodshed, destroy, defeat, pogrom. crush. savage. kill
dispatch, slay, exterminate, snuff.
Other relevant words:
carnage, thrashing, trouncing, overcome, bloodletting, mow down, crush, thrash, HIT, euthanasia, bloodshed, walloping, defeat, beat, attack, genocide, whipping, overpower, drubbing, destroy, smash, debacle, savage, bump off, bloodbath, pogrom.

Usage examples for slaughter

  1. The deadly ray- gun on the roof wrought swift slaughter amongst them, but some got into the darkness beyond vision of the icy gray eyes. – Hawk Carse by Anthony Gilmore
  2. He could easily do this, but fearful slaughter would be the inevitable result. – Henry IV, Makers of History by John S. C. Abbott
  3. The loss fell chiefly on the followers of Almagro But the slaughter was not confined to the heat of the action. – History-of-the-Conquest-of-Peru-with-a-preliminary-view-of-the-civilization-of-the-Incas by Prescott, William Hickling