If you drop your candy wrappers and soda cans on the ground instead of in the trash can (or recycling bin), you're a litterbug. In many cities, you can be fined for being a litterbug.
The informal litterbug is the perfect scornful name for someone who doesn't care about keeping the city, beach, or school grounds clean. In Britain, a litterbug might find himself referred to instead as a "litter lout." The New York City subway system is often credited with coining the word litterbug in the 1940s, from the model of jitterbug, a dance that was popular in the 1930s.