The word mug has several meanings:

1. A large cup with a handle, usually for hot drinks like coffee, tea, or hot chocolate. Unlike a teacup, which is small and delicate, a mug is sturdy and holds more liquid. People often have favorite mugs they use every morning, sometimes decorated with pictures, jokes, or souvenirs from places they've visited.
2. To attack and rob someone, usually on the street. A mugger might threaten someone to steal their wallet or phone. When someone gets mugged, they're the victim of this kind of robbery.
3. A person's face, used informally and sometimes rudely. If someone says, “I don't want to see your mug around here,” they mean your face.
4. To make exaggerated facial expressions, especially for a camera or audience. Actors sometimes mug for the camera by making silly faces to get attention or laughs. A comedian might mug during a performance, pulling faces to emphasize a joke.