FATGUYMEST Share definition Flag fat fuckin admin (...bitch!) of the mestboard, avid pot smoker and beer drinker. computer nerd for a living. a great guy. "Who's that crazy guy dancing up on stage?" "Don't mind him...it's just FATGUYMEST!" FATGUYMEST by your worst nightmare! May 11, 2004 0 0 Get merch Get the FATGUYMEST mug. Buy Now — $32.95 See more merch