A renegade is a person who has deserted their cause or defied convention; they're rebels and sometimes outlaws, or even traitors.
A long, long time ago, a renegade was a Christian person who decided to become Muslim. That definition is pretty outdated, as these days a renegade is anyone who breaks laws or expectations to do their own thing or join the other side. It might sound kind of cool to be a renegade, like some rogue action hero. But in general, renegade actions are frowned, not smiled, upon.