A smart aleck is someone who makes annoying, cocky remarks to show off how clever they think they are. The term describes a person who can't resist making sarcastic comments or giving unwanted advice, usually at exactly the wrong moment.

Picture a classmate who interrupts the teacher with a smirky “Well, actually...” correction, or someone who responds to every simple question with an eye-rolling joke instead of a helpful answer. That's classic smart aleck behavior. The person might actually be intelligent, but they use their cleverness to irritate people rather than help them.

What makes someone a smart aleck isn't being smart or funny. It's the combination of showing off and bad timing. When your mom asks you to clean your room and you reply “I was just about to do that” in a sarcastic tone, that's being a smart aleck. When a friend asks for help with homework and you say “Maybe if you actually paid attention in class...” instead of just helping, you're acting like a smart aleck.

The term is mildly insulting but not harsh. It's the kind of thing an exasperated teacher or parent might say: “Don't be such a smart aleck!” People sometimes call it being a wise guy or a smarty-pants. The key is recognizing when your cleverness crosses the line from funny to obnoxious.