adytum, ashram, cabinet, cell, cloister, closet, den, hermitage, hideaway, hideout, hiding place, ivory tower, lair, mew, privacy, recess, retreat, sacrarium, sanctuary, sanctum, sanctum sanctorum, secret place, the holy, the ineffable, the inenarrable, the inexpressible, the numinous, the unspeakable, the unutterable