rack um Share definition Flag What you tell your friend to do when you want them to rack you a line of coke, meth, or anything you want to sniff through your nose. "Hey Michael!", Richard said. "Rack um and pass me the straw then grab the wheel!" rack um by rack master October 28, 2006 0 0 Get merch Get the rack um mug. Buy Now — $32.95 See more merch