A fool is someone who acts without good judgment or common sense, often making silly mistakes that could have been avoided with a little thought. When your friend tries to ride their bike down the stairs “just to see what happens,” you might call that a foolish decision. A fool may not learn from experience or advice, repeating the same mistakes over and over.

In older stories and plays, a fool or jester was actually a job: an entertainer who told jokes and acted silly to make nobles and kings laugh. These court fools were often clever people who used humor and playful tricks to say things others couldn't. Shakespeare's plays feature wise fools who speak truth through jokes.

The word also appears in many expressions. To fool around can mean to waste time playing instead of working. Foolproof means so simple that even a careless person couldn't mess it up. If someone tries to fool you, they're attempting to trick or deceive you into believing something false.

When someone calls you a fool, they usually mean you're acting unwisely in that moment, not that you lack intelligence forever. We all make foolish choices sometimes, and we can learn from them.