What is "muhakkima"

Muhakkima (Arabic محكمة) was one of the earliest groups to form within the Kharijite movement. The name of the movement is derived from its opposition to arbitration as a means to determine a successor, on the grounds that "judgement belongs to Allah alone (lā ḥukma Illā li-llah)."

The Muhakkima were those early opponents of the Caliph Ali ibn Abi Talib. Among the movement's leaders was Abdullah ibn Wahb al-Rasibi. They were defeated at the Battle of Nahrawan.