McSlut Share definition Flag a girl whose so slutty, shes even willing to fornicate behind the dumpster of a filth ridden McDonalds. that McSlut gummed me behind that big green dumpster in the McDonald's parking lot. McSlut by babolonfivefanatic November 27, 2006 0 0 Get merch Get the McSlut mug. Buy Now — $32.95 See more merch