A bully is someone who repeatedly hurts, threatens, or picks on people who have less power or can't easily defend themselves. Unlike a fair fight or honest argument, bullying is one-sided: the bully chooses targets who seem vulnerable or different.

Bullies might push smaller kids around at recess, spread cruel rumors about classmates, or mock someone's appearance or interests. Some bullies use physical force, while others use words or social pressure. Modern bullies might send mean messages online, which is called cyberbullying.

Many bullies feel powerless in their own lives. They might be struggling at home or feeling insecure, so they try to feel stronger by making others feel weak. This doesn't excuse bullying, but it helps explain why people do it.

Standing up to bullying takes courage, whether that means confronting it directly, telling a trusted adult, or supporting someone being bullied. Schools and communities work hard to stop bullying because it can seriously harm both the target's confidence and sense of safety.

As a verb, to bully means to act this way toward someone: “He would bully younger students into giving him their lunch money.” People also use “bully” more loosely, like when a big country bullies smaller neighbors into unfair agreements.