Leaders of union possibly go for recovery (6)
I believe the answer is:
upturn
'for recovery' is the definition.
(I've seen this before)
'leaders of union possibly go' is the wordplay.
'leaders of' suggests taking the first letters.
'go' becomes 'turn' (as in one's go or turn in a game).
The initial letters of 'union possibly' is 'up'.
'up'+'turn'='UPTURN'
(Other definitions for upturn that I've seen before include "Improvement, better trend in business" , "Recovery" , "Improvement in business activity" , "Improvement in fortunes" , "Improved trend in business or fortune" .)