hackin' Share definition Flag a different way to say freakin/fuckin. its an adjective. fred on youtube uses it a lot. Fred: Hey, it's Fred! And I'm really hackin' mad right now because Judy hasn't IMed me back all day! haha...fred. hackin' by coolbeans June 14, 2008 0 0 Get merch Get the hackin' mug. Buy Now — $32.95 See more merch