Past name for Stravinsky ballet (4)
I believe the answer is:
agon
'stravinsky ballet' is the definition.
(I've seen this before)
'past name' is the wordplay.
'past' becomes 'ago' (similar in meaning).
'name' becomes 'n' (common abbreviation e.g. on forms).
'ago'+'n'='AGON'
'for' acts as a link.
(Other definitions for agon that I've seen before include "Conflict" , "archaic festival" , "Stravinsky ballet" , "Greek contest" , "Struggle" .)