Dumber Than Snape Share definition Flag One who is the dumbest of the dumb, dumber than anyone else by comparison. Becky thinks that Boston is a state! Man, she's dumber than Snape. Dumber Than Snape by The Goddamn Batcolin January 4, 2012 0 0 Get merch Get the Dumber Than Snape mug. Buy Now — $32.95 See more merch