Women call boxing amateur a complete failure (7)
I believe the answer is:
washout
'a complete failure' is the definition.
(I've seen this before)
'women call boxing amateur' is the wordplay.
'women' becomes 'w'.
'call' becomes 'shout' ('shout' can be a synonym of 'call'**).
'boxing' means one lot of letters goes inside another ('box' can mean contain, as in to put in a box).
'amateur' becomes 'a'.
'w'+'shout'='wshout'
'wshout' placed around 'a' is 'WASHOUT'.
(Other definitions for washout that I've seen before include "Cancelled test, for example" , "A complete failure - too much rain" , "Failure - cancellation" , "Disappointing failure" , "Cancelled event - utter failure" .)