flounder UK /ˈflaʊ̯ndəː/US /ˈflaʊ̯ndɚ/verb 4noun 3forms 3phrases 1 verb4 •To flop around as a fish out of water. •To act clumsily or confused; to struggle or be flustered.He gave a good speech, but floundered when audience members asked questions he could not answer well. •To be in serious difficulty.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 •To make clumsy attempts to move or regain one's balance.Robert yanked Connie's leg vigorously, causing her to flounder and eventually fall. noun3 •A European species of flatfish having dull brown colouring with reddish-brown blotches; fluke, European flounder (Platichthys flesus). •(US, Canada) Any of various flatfish of the family Pleuronectidae or Bothidae. •A bootmaker's tool for crimping boot fronts. formsfloundered · floundering · flounders Phrases with flounder pound one's flounderTo masturbate (one's penis).