Source : Webster's Revised Unabridged Dictionary (1913)

Blunder \Blun"der\, v. i. [imp. & p. p. {Blundered}; p. pr. &
   vb. n. {Blundering}.] [OE. blunderen, blondren, to stir,
   confuse, blunder; perh. allied to blend to mix, to confound
   by mixture.]
   1. To make a gross error or mistake; as, to blunder in
      writing or preparing a medical prescription. --Swift.

   2. To move in an awkward, clumsy manner; to flounder and
      stumble.

            I was never distinguished for address, and have
            often even blundered in making my bow. --Goldsmith.

            Yet knows not how to find the uncertain place, And
            blunders on, and staggers every pace. --Dryden.

   {To blunder on}.
      (a) To continue blundering.
      (b) To find or reach as if by an accident involving more
          or less stupidity, -- applied to something desirable;
          as, to blunder on a useful discovery.