Snarl up the net, going out to fish (8)
I believe the answer is:
entangle
'snarl up' is the definition.
(thesaurus)
'the net going out to fish' is the wordplay.
'going out' indicates an anagram (out can mean wrong or inaccurate).
'to fish' becomes 'angle' (angling is a kind of fishing).
'net' is an anagram of 'ent'.
'ent'+'angle'='ENTANGLE'
(Other definitions for entangle that I've seen before include "Prize cup" , "caught up" , "Snare" , "Twist together into a confusing mass" , "Ensnare" .)