There are three ways to stump: you can ask someone a question they can't answer, you can travel making political speeches, or you can stomp.
Stump can mean many things as a verb. The most common use is when someone — like a teacher — asks a question that no one can answer. That's a case of the teacher stumping the class. Also, politicians traveling through a district, making speeches are stumping, giving what are called stump speeches. Once in a while, to stump means the same thing as two similar words, stomp and stamp. If you're stumping, stomping, and stamping around, you're making a lot of noise with your feet.