Standards for judging writer sacrificing wife taken in by spies (8)
I believe the answer is:
criteria
'standards for judging' is the definition.
(I've seen this before)
'writer sacrificing wife taken in by spies' is the wordplay.
'sacrificing' suggests deleting specific letters.
'wife' becomes 'w'.
'taken in by' means one lot of letters goes inside another.
'spies' becomes 'cia'.
'writer' with 'w' removed is 'riter'.
'riter' inserted into 'cia' is 'CRITERIA'.
(Other definitions for criteria that I've seen before include "References points, standards" , "Principles on which to base a judgement" , "Standards, yardsticks" , "Principles for decision" , "Erratic, I embrace standards" .)