A mutineer is a person who joins a mutiny: someone who is supposed to obey — most often a sailor or a soldier — but who refuses the person in charge and tries, with others, to take control. It is not a word for any rebel. A student who skips class is not a mutineer; a sailor who helps seize the ship is. The word feels a little old and story-like. You meet it in history and in adventure books more than at the dinner table, though the news will still use it when a crew really does rise up. The noun (the person) is the one you need; a verb “to mutineer” exists but is rare.