schismatic

late 14c., scisme, sisme, cisme, "outward dissension within the church," producing two or more parties with rival authorities, from Old French scisme, cisme "a cleft, split" (12c.) and directly from Church Latin schisma, scisma (in Medieval Latin also cisma), from Greek skhisma (genitive skhismatos) "division, cleft," from stem of skhizein "to split"  (from PIE root *skei- "to cut, split").

The Greek word was applied metaphorically in the New Testament to divisions in the Church (I Corinthians xii.25), 

The classical spelling was restored 16c., but the pronunciation is unsettled. The general sense of "disunion, division, separation" is from early 15c. Historically, often in reference to the Great Schism (1378-1417) in the Western Church.