Slack Rack Share definition Flag Extremely attractive female who has a decidedly noticeable lack of cleavage. "Dude Ashley's hot!" "She okay... She would be so much hotter if she didn't have that Slack Rack!" Slack Rack by Harry James-Parker September 24, 2014 0 0 Get merch Get the Slack Rack mug. Buy Now — $32.95 See more merch