When you rebel against your parents by dyeing your hair green and staying out without calling, you are acting in a way that questions both their authority and their rules about what is right and acceptable.
A rebel is someone who fights authority. The story of a rebel often finds its way into books and movies. In the 1950s film "Rebel without a Cause," a teenager rebels against his parents. In the "Star Wars" movies, the Jedi rebel against the Empire. A rebel, whether the cause they are fighting for is just or not, is always the underdog. One pronunciation hint, rebel as a noun has the stress on the first syllable and as a verb on the second.