Takfiri

Hasan Nasrallah talked about Takfiri groups in Syria.  Takfiris are those who rush to declare the infidelity of their opponents, even if they are fellow Muslims who don't share their particular exclusivist and conservative view and practice of religion.  It is not in any way exclusive to Sunnis: Hizbullah itself under Subhi Tufayli was a takfiri party.