Mahdi (i.e. religious leader), a name given to any Mohammedan fanatic who arises in the interest of the Mohammedan faith, summons the Moslems to war, and leads them to repel the infidel; a kind of Mohammed Messiah armed with the sword for the conquest of the world to the faith.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Mahatma * Mahdi, Mohammed Ahmed