A weirdo is someone who thinks or behaves differently from most people.
When people call someone a weirdo, they usually mean that this person has some quirky habits or interests. It doesn't always have to be a bad thing - being different can be refreshing and interesting. For example, if your friend loves wearing bright colors and has a collection of vintage toys, you might jokingly say they're a bit of a weirdo. But if someone at school is bullied for their unique style or interests, it's not okay to call them a weirdo in a mean way.
A strange, odd, eccentric person.
