To tease someone means to playfully make fun of them or gently poke at something about them, usually in a lighthearted way that isn't meant to hurt. When your brother teases you about your messy handwriting, he's joking around, not trying to be cruel. Friends often tease each other about small quirks or habits: “Nice hat!” someone might say with a grin when you're wearing something unusual.

Teasing is meant to stay playful and should stop if it bothers someone. There's an unspoken understanding that everyone's just having fun. But teasing can cross a line and become mean if it targets something someone feels sensitive about, continues after they've asked you to stop, or happens in front of others in an embarrassing way. The difference matters: one makes people laugh together, the other makes someone feel small or hurt.

The word can also mean to deliberately tempt or frustrate someone, like when a trailer teases an upcoming movie by showing just enough to make you curious. Or when your sister holds up a cookie, offers it to you, then pulls it away laughing. That's teasing too: creating anticipation or mild frustration, though it should still be in fun.