District using country club for grand social gathering (7)
I believe the answer is:
reunion
'social gathering' is the definition.
(reunion is a kind of social gathering)
'district using country club for grand' is the wordplay.
I cannot quite see how this works, but
'district' could be 'union' (Union is an example) and 'union' is found in the answer.
The remaining letters 're' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for reunion that I've seen before include "Get-together of old friends" , "Annual get-together as of past pupils" , "Meet-up of old friends" , "Meeting of old friends" , "overseas region of France" .)