Kafir ( ; plural ; feminine ) is an Arabic term (from the root K-F-R "to cover") used in an Islamic doctrinal sense, usually translated as "unbeliever," "disbeliever," or "infidel". It is used as a derogatory term. The term alludes to a person who rejects or disbelieves in God and the religious truth revealed through the mission of the Islamic Prophet Muhammad, and thus demonstrates ingratitude towards God; denies, refuses to accept the dominion and authority of God; or otherwise does not heed the beliefs and prescriptions held by the religion of Islam. Unbelief is called kufr. Kafir is sometimes used interchangeably with mushrik (, those who commit polytheism), another type of religious wrongdoer mentioned frequently in the Quran and Islamic works. The practice of declaring another self-professed Muslim a kafir is known as takfir.