Victory immediately required for fan (6)
I believe the answer is:
winnow
'for fan' is the definition.
(synonyms)
'victory immediately required' is the wordplay.
'victory' becomes 'win' (a win is a victory).
'immediately' becomes 'now' (I've seen this before).
'required' means one lot of letters go next to another.
'win'+'now'='WINNOW'
(Other definitions for winnow that I've seen before include "Sift out" , "Fan" , "Separate the wheat from the chaff" , "Blow air through (grain) to remove chaff" , "Dehusk grain using air currents" .)