Definition of "flounder"

flounder¹

/ˈflaʊndɚ/

noun
plural flounder or flounders
1. A European species of flatfish having dull brown colouring with reddish-brown blotches; fluke, European flounder, Platichthys flesus.
2. (Canada, US) Any of various flatfish of the family Pleuronectidae or Bothidae.
3. A bootmaker's tool for crimping boot fronts.

flounder²

/ˈflaʊndɚ/

verb
third-person singular simple present flounders, present participle floundering, simple past and past participle floundered
1. (intransitive) To act clumsily or confused; to struggle or be flustered.
  Quotations
  They have floundered on from blunder to blunder.
  1859–1860, William Hamilton, edited by H[enry] L[ongueville] Mansel and John Veitch, Lectures on Metaphysics and Logic […], volumes (please specify |volume=I to IV), Edinburgh, London: William Blackwood and Sons
2. (intransitive) To flop around as a fish out of water.
3. (intransitive) To make clumsy attempts to move or regain one's balance.
4. To be in serious difficulty.
  Quotations
  Meanwhile bus and tram competition was causing the Central London Railway to flounder after its early success, and as for the City & South London ... that had always floundered.
  2012, Andrew Martin, Underground Overground: A passenger's history of the Tube, Profile Books, page 159