The holy fool, Greek salos and Russian yurodivy, renounces reason and respectability, living in rags and behaving outrageously, to expose the folly of worldly wisdom and to hide his own sanctity. Symeon of Emesa and Basil of Moscow are famous examples. Paul spoke of being fools for Christ’s sake.
Holy fool
One who feigns madness or flouts convention for Christ’s sake, especially in Byzantine and Russian tradition.
Also: yurodivy, fool for Christ