from The Century Dictionary and Cyclopedia
- n. One who holds that the Mahdi whose coming was foretold by Mohammed has already appeared; specifically, one who holds that the Mahdi has already appeared in the person of Mohammed Abu el-Qasim, the twelfth Imam, who is supposed to be concealed in some secret place awaiting the hour of his manifestation. The Shiahs in general hold this view. Also Mahdist.
Sorry, no etymologies found.