Fool (n.)(v.) - This is not an April fools gag.
Silly, stupid or ignorant person.
To deceive someone intentionally.
History & Etymology
We’ve all heard someone called a wind bag, but what is a wind bag, and what does it have to do with the word fool.
Well a wind bag is a bag full of what essentially amounts to nothing, nothing but air. Well going back to Old French the word to describe a wind bag or what we would call today a bellows, was fol. Fol also meant insane person, idiot or jester. This French word comes from its original Latin root follis meaning bellows or leather bag.
This is where the word fool came from. Calling someone a fool refers to their empty headedness or verbos expression of terrible ideas.