Urf

ʿUrf (Arabic: العرف) is an Arabic Islamic term referring to the custom, or 'knowledge', of a given society. It can also be translated as customary law. To be recognized in an Islamic society, ʿurf must in principle be compatible with Sharia, but in practice tensions sometimes exist between the representatives of ʿurf and those of Sharia. When applied, it can lead to the deprecation or inoperability of a certain aspect of fiqh (Islamic jurisprudence).

ʿUrf is a source of Islamic legal rulings where there are no explicit primary texts of the Qur'an and Sunnah specifying the ruling, making it a form of customary law. ʿUrf can also specify something generally established in the primary texts.