Bolster failing target for fishermen? (7)
I believe the answer is:
lobster
'target for fishermen?' is the definition.
'bolster failing' is the wordplay.
'failing' indicates an anagram.
'bolster' is an anagram of 'LOBSTER'.
(Other definitions for lobster that I've seen before include "Large marine decapod" , "one to loft a > shellfish?" , "Large, strong-jawed crustacean" , "Lets bro have the shellfish" , "Crustacean caught in pot" .)