Webster's Revised Unabridged Dictionary · 1913

Flounder

Flounder , noun

[Compare Swedish flundra; akin to Danish flynder, Icelandic fly{not transcribed}ra, German flunder, and perh. to English flounder, v.i.]

1.
(Zoology) A flatfish of the family Pleuronectida, of many species.

The common English flounder is Pleuronectes flesus. There are several common American species used as food; as the smooth flounder (P. glabra); the rough or winter flounder (P. Americanus); the summer flounder, or plaice (Paralichthys dentatus), Atlantic coast; and the starry flounder (Pleuronectes stellatus).

2.
(Bootmaking) A tool used in crimping boot fronts.

Flounder , intransitive verb

[Compare Dutch flodderen to flap, splash through mire, English 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.
They have floundered on from blunder to blunder. — Sir W. Hamilton

Flounder , noun

The act of floundering.