Source : Webster's Revised Unabridged Dictionary (1913)

Bungler \Bun"gler\, n.
   A clumsy, awkward workman; one who bungles.

         If to be a dunce or a bungler in any profession be
         shameful, how much more ignominious and infamous to a
         scholar to be such!                      --Barrow.

Source : WordNet®

bungler
     n : someone who makes mistakes because of incompetence [syn: {blunderer},
          {fumbler}, {bumbler}, {stumbler}, {sad sack}, {botcher},
          {butcher}, {fuckup}]