jackbag
A person you don’t know, but they’re either a total idiot or a smelly, brainless, self-centered piece of garbage. You don’t know which one yet.
That guy in my math class is a jackbag. He tried to talk during a test and got yelled at.
My new neighbor is a jackbag. He tried to start a fight with my dog.
That kid in the lunch line is a jackbag. He tried to steal my chips.