Meaning

noun a person who lacks good judgment

noun a person who is gullible and easy to take advantage of

noun a professional clown employed to entertain a king or nobleman in the Middle Ages

originFrom Middle English fol (“fool”), from Old French fol (cf. modern French fou (“mad”)) from Latin follis. Doublet of fals and follis. Displaced native Old English dwæs.

Etymology from Wiktionary, CC BY-SA 3.0