Takfir or takfīr (Arabic: تكفير, romanized: takfīr) is an Arabic and Islamic term which denotes excommunication from Islam of one Muslim by another, i.e. accusing another Muslim to be an apostate. The word is found neither in the Quran nor in the ḥadīth literature; instead, kufr ("unbelief") and kāfir ("unbeliever") and other terms employing the same triliteral root k-f-r appear. "The word takfīr was introduced in the post-Quranic period and was first done by the Khawarij," according to J. E. Campo. The act which precipitates takfīr is termed mukaffir. A Muslim who declares another Muslim to be an unbeliever or apostate is a takfīri ("excommunicational").