flounderer

As a noun flounderer

is one who flounders, who behaves clumsily without direction.

As a verb floundered is

(flounder).

As nouns the difference between flounder and flounderer

is that flounder is a European species of flatfish having dull brown colouring with reddish-brown blotches; fluke, European flounder, species: Platichthys flesus while flounderer is one who flounders, who behaves clumsily without direction.

As a verb flounder

is to flop around as a fish out of water.