anchorite (n.)

mid-15c., "hermit (especially those of the Eastern deserts in the two centuries after c. 300 C.E.), recluse, one who withdraws from the world for religious reasons," from Medieval Latin anchorita, Late Latin anchoreta, from Greek anakhoretes, literally "one who has retired," agent noun from anakhorein "to retreat, go back, retire (from battle, the world, etc.)," from ana "back" (see ana-) + khorein "withdraw, give place," from khoros "place, space, free space, room," from PIE root *ghē- "to release, let go; be released." Replaced Old English ancer, from Late Latin anchoreta. Related: Anchoritic.

There is, perhaps, no phase in the moral history of mankind of a deeper or more painful interest than this ascetic epidemic. A hideous, sordid, and emaciated maniac, without knowledge, without patriotism, without natural affection, passing his life in a long routine of useless and atrocious self-torture, and quailing before the ghastly phantoms of his delirious brain, had become the ideal of the nations which had known the writings of Plato and Cicero, and the lives of Socrates and Cato. [Lecky, "History of European Mortals"]