noun

• (obsolete) Murder.
  "The tyrannous and bloody act is done,— The most arch deed of piteous massacre That ever yet this land was guilty of."
• (figuratively) Any overwhelming defeat, as in a game or sport.

verb

• (transitive) To kill in considerable numbers where little or no resistance can be made, with indiscriminate violence, without necessity, and contrary to civilized norms. (Often limited to the killing of human beings.)
  "If James should be pleased to massacre them all, as Maximilian had massacred the Theban legion"
• (transitive, figuratively) To win against (an opponent) very decisively.
• (transitive, figuratively) To perform (a work, such as a musical piece or a play) very poorly.
• (transitive, proscribed) To kill with great force or brutality.
  "Look how they massacred my boy."