Struggle clumsily (8)
I believe the answer is:
flounder
'struggle clumsily' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for flounder that I've seen before include "Small flatfish" , "Have difficulty" , "Move clumsily like flatfish?" , "small swimmer" , "Fish -- stumble helplessly" .)