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

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