Leaders of union possibly go for recovery (6)
I believe the answer is:
upturn
'recovery' is the definition.
(I've seen this in another clue)
'leaders of union possibly go' is the wordplay.
'leaders of' says to take the initial 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'
'for' acts as a link.
(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" .)