noun

• (religion) A formal division or split within a religious body.
  "The schism between Sunnis and Shias happened quite early in Islamic history."
• (Catholicism) a split within Christianity whereby a group no longer recognizes the Bishop of Rome as the head of the Church, but shares essentially the same beliefs with the Church of Rome. In other words, a political split without the introduction of heresy.

verb

• (transitive) To split, divide (a group or organization).
  "“This is going to schism Maga terribly online,” Kirk said. “You're going to see—I don't want to say a Maga civil war, but it's going to be a Maga online food fight that is going to be very hard to navigate.”"