Ghulāt (Arabic: غلاة; lit. "extremists", the adjectival form of ghuluww), is a term used in the theology of Shia Islam to describe some minority Muslim groups who either ascribe divine characteristics to figure of Islamic history -- mostly, but not always a member of Muhammad's family (Ahl al-Bayt) -- or hold beliefs deemed deviant by mainstream Shi'i theology. In later periods, this term was used to describe any Shi'i group not accepted by the Zaydis, orthodox Twelvers, and sometimes the Ismailis.
The usage derives from the idea that the importance or the veneration of such a religious figure has been "exaggerated".
Mainstream Shi'i groups, especially the Imamiyya, have identified three acts that have been judged as "extremism" (ghuluww). These acts of heresy are: the claim that God sometimes takes abode in the bodies of the Imams (ḥulūl), the belief in metempsychosis (tanāsukh), and considering Islamic law to be not obligatory (ibāḥa), similar to antinomianism.