Takfir

In Islamic law, takfir or takfeer (Arabic: تكفير‎‎ takfīr) refers to the practice of excommunication, one Muslim declaring another Muslim as kafir (non-believer). The act which precipitates takfir is termed the mukaffir. An ill-founded takfir accusation is a major forbidden act.

Some Muslims consider takfir (declaring someone a kafir) to be a prerogative of either the Prophet—who does that through Divine revelation—or the State which represents the collectivity of the Ummah (the whole Muslim community).

The declaration of takfir may be made if the alleged Muslim declares himself a kafir, but more typically applies to a judgement that an action or statement by the alleged Muslim indicates his knowing abandonment of Islam.

Orthodox Islamic law normally requires stringent evidence for such accusations. In many cases an Islamic court or a religious leader, an alim must pronounce a fatwa (legal judgement) of takfir against an individual or group.

There are disputes among different schools of religious thought as to what constitutes sufficient justification for declaring takfir:

The orthodox Sunni position is that sins generally do not prove that someone is not a Muslim, but denials of fundamental religious principles do. Thus a murderer, for instance, may still be a Muslim, but someone who denies that murder is a sin is a kafir if he is aware that murder is considered a sin in Islam.

The Murjites argued that anyone who called themselves Muslim should be considered Muslim.

The Mu'tazilites (followed by the Zaidiyyahs) advocated what they saw as a middle way, whereby grave sinners were categorized neither as believers nor as kafirs.

Some of the early medieval Kharijites concluded that any Muslim who sinned ceased to be a Muslim, while others concluded that only major sin could cause that.

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