Marstupial Share definition Flag A person, typically a vapid egocentric yuppie woman, who carries her dog in a pouch type bag. Derived from the root Marsupial. Wow, that cute little terrier in that marstupial's purse looks depressed and bored. Marstupial by Dinkle McDink June 10, 2011 0 0 Get merch Get the Marstupial mug. Buy Now — $32.95 See more merch