1. A synonym for "rapist"
2. A closet homosexual who feels the need to impress other closet homosexuals by being a faggot and raping drunk girls
3. One who lacks the ability to think and/or act without following a crowd.
Hey, don't be a fratboy, stop raping my sister.
Hey is that an Abercrombie shirt? And hair gel? What are you, a fratboy?