Treasurer’s problem concerning specific objective (9)
I believe the answer is:
overspend
'treasurer's problem concerning specific objective' is the definition.
I can't judge whether this defines the answer.
'concerning specific objective' is the wordplay.
'concerning' becomes 'over' (both can mean relating to).
'specific objective' becomes 'spend' (I can't explain this - if you can you should believe this answer much more).
'over'+'spend'='OVERSPEND'
Can you help me to learn more?
(Other definitions for overspend that I've seen before include "Use up too much money" , "Consume too much" , "Buy too much" , "splurge" , "To exceed one's budget" .)