Wiktionary
takfir
vb. To excommunicate another Muslim.
Wikipedia
Takfir
In Islamic law, takfir or takfeer ( ) 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.
Usage examples of "takfir".
It is hard to say, though in the past, the Brotherhood maintained links with radical groups like Takfir Wa Hegira (Purging and Spiritual Passage) and Jihad (Holy War), the latter of which carried out the assassination of Sadat.