A mugging is the attack: someone is stopped in a public place and robbed, often with a shove or a threat. Police and newspapers use the word for the event. The person who does it is a mugger; the verb is to mug. It is serious, everyday crime English, not a joke in its main use. Though actually, people sometimes say “I got mugged” about a painful bill or a very high price, as a dark little joke — that stretch is informal and is not a real street attack. Keep the core picture: public place, person, things taken under fear.