stump·er \ˈstəmpə(r)\noun (-s) : one that stumps: as a.: one that removes tree stumps b.: wicketkeeper c.: a perplexing or difficult question : poser < a real question … a stumper — Benjamin DeMott > d.: stump speaker < the most indefatigable campaigner and best … stumper — Hodding Carter > e.: one that adjusts the mandrel on a tube-welding machine f.: an operator of a felting machine