Cunning traps for fish (5)
I believe the answer is:
sprat
'fish' is the definition.
(sprat is a kind of fish)
'cunning traps' is the wordplay.
'cunning' indicates an anagram.
'traps' anagrammed gives 'SPRAT'.
'for' acts as a link.
(Other definitions for sprat that I've seen before include "Small marine fish" , "chap giving richer course material to the Dutch" , "Small herring-type fish" , "Tiny fish" , "It's set to catch a mackerel" .)