Fuckupbrah is an abbreviation for the phrase "Shut the fuck up, brah." Originally heard in Lacey Township NJ, it has spread all over south Jersey and is used by tools and guidos alike.
Tony- Yo Joey, I saw your girl hookin up with that frat dood last night at the party!
Joey- YO, FUCKUPBRAH! I thought I told you not to talk about Jenny like that!!