To tattle means to report someone else's minor misbehavior to an authority figure, usually to get them in trouble rather than to prevent harm. When a student tattles on their classmate for chewing gum or whispering during silent reading, they're running to tell the teacher about small rule-breaking that doesn't really affect anyone else.

Tattling is different from reporting something serious. If you see someone being bullied or hurt, telling a teacher isn't tattling: it's helping prevent harm. But if you're constantly pointing out every tiny thing your sibling does wrong, hoping they'll get punished, that's tattling. A tattletale (someone who tattles frequently) can annoy both adults and other kids because their goal seems to be getting others in trouble rather than making things better or safer.

The tricky part is learning the difference. Is your brother about to touch a hot stove? Telling an adult immediately is important. Did your brother get an extra cookie? That probably isn't worth reporting. When you're genuinely trying to protect someone or prevent a real problem, you're reporting. When you're just trying to get someone else in trouble for breaking small rules, you're tattling.