Do you know ghouls from goblins and ghosts?
early 14c., "free from spiritual pollution," from Old French purefier "purify, cleanse, refine" (12c.), from Latin purificare "to make pure," from purus "pure" (see pure) + root of facere "to make" (see factitious). Meaning "free from extraneous matter" is recorded from mid-15c. Related: Purified; purifying.