A know-it-all is someone who acts like they have all the answers and won't listen when others try to share ideas or information. The term describes a person who constantly corrects others, interrupts with their own explanations, and makes people around them feel small or foolish.

Everyone knows things others don't, and sharing knowledge is wonderful. But a know-it-all doesn't just share what they know: they make every conversation feel like a lecture. When a classmate explains how they solved a problem, the know-it-all jumps in with “Actually, you should have...” When friends discuss a movie, the know-it-all explains every detail they already knew about it, as if no one else could possibly understand.

The worst part about being a know-it-all isn't being wrong (everyone's wrong sometimes). It's the attitude: acting superior, refusing to admit uncertainty, and treating other people's knowledge as worthless. A true expert knows how much they still have to learn and listens carefully to others. A know-it-all pretends to be an expert but mostly just irritates people.

If someone calls you a know-it-all, it's worth thinking about whether you've been sharing knowledge or just showing off. The difference matters more than whatever fact you were so eager to share.