The Collaborative International Dictionary of English v.0.48:

Flounder \Floun"der\, v. i. [imp. & p. p. Floundered; p. pr. &
   vb. n. Floundering.] [Cf. D. flodderen to flap, splash
   through mire, E. flounce, v.i., and flounder the fish.]
   To fling the limbs and body, as in making efforts to move; to
   struggle, as a horse in the mire, or as a fish on land; to
   roll, toss, and tumble; to flounce.
   [1913 Webster]

         They have floundered on from blunder to blunder. --Sir
                                                  W. Hamilton.
   [1913 Webster]