Takfir or takfeer (Arabic: تكفير, romanized: takfīr) denotes excommunication from Islam of one Muslim by another, i.e. accusing another Muslim to be an apostate.[1][2][3] The word is found neither in the Quran nor in the hadiths. Kufr and kafir and other terms employing the same triliteral root k-f-r appear.[4] "The word takfir was introduced in the post-Quranic period and was first done by the Khawarij," according to J. E. Campo.[5] The act which precipitates takfir is termed mukaffir. A Muslim who declares another Muslim to be an unbeliever or apostate is a takfiri.[6]
Since according to the traditional interpretations of sharia law the punishment for apostasy is the death penalty,[3] and potentially a cause of strife and violence in the Muslim community (Ummah),[6] an ill-founded takfir accusation was a major forbidden act (haram) in Islamic jurisprudence,[7] with one hadith declaring that one who wrongly declare a Muslim an unbeliever is himself an apostate.[8][9] In the history of Islam, a sect originating in the 7th century CE known as the Kharijites carried out takfir and were a source of insurrection against the early caliphates for centuries.[10] Traditionally, Islamic scholars (Ulema) have held that only they were authorized to declare someone a kafir (unbeliever), that all the prescribed legal precautions should be taken before declaring takfir,[11] and that those who profess the Islamic faith should be exempt.[6]
Starting in the mid to late 20th-century, some individuals and organizations in the Muslim world began to apply takfir accusations not only against those that they perceived as stray deviant and lapsed Muslims, but Islamic governments and societies as well.[3][12][13][14] In his widely influential book Milestones, Egyptian Islamist ideologue Sayyid Qutb preached that all of the Muslim world had fallen into a state of collective apostasy or jahiliyah (a state of pre-Islamic ignorance) several centuries ago, having abandoned the use of sharia law, without which (Qutb held) Islam cannot exist.[3][12] Qutb affirmed that since Muslim government leaders (along with being cruel and evil) were actually not Muslims but apostates preventing the revival of Islam, the use of "physical force" should be used to remove them.[3][12] This radical Islamist ideology, called "takfirism", has been widely held and applied by numerous Islamic extremists, terrorists, and jihadist organizations in the late 20th and early 21st-centuries, to varying degrees.[3][12][13][14][15][16]
Since the latter half of the 20th century, takfir has also been used for "sanctioning violence against leaders of Islamic states"[17] who do not enforce sharia or are otherwise "deemed insufficiently religious".[13] This application of takfir has become a "central ideology"[17] of insurgent Wahhabi-Salafi jihadist extremist and terrorist groups,[12][15][18] particularly al-Qaeda and ISIL/ISIS/IS/Daesh,[3][12][14][15] who have drawn on the ideas of the medieval Islamic scholars Ibn Taymiyyah and Ibn Kathir, and those of the modern Islamist ideologues Sayyid Qutb and Abul A'la Maududi.[12][15][16] The practice has been denounced as deviant by mainstream Muslim groups and mainstream Islamic scholars such as Hasan al-Hudaybi (d. 1977) and Yusuf al-Qaradawi.[17]
Kufr and kafir and other terms employing the root k-f-r are found both in the Quran and the hadiths, but the word "takfir" to declare Muslims as "kafir" is found in neither.[4] "The word takfir was introduced in the post-Quranic period and was first done by the Khawarij," according to J. E. Campo.[19]