Drive affected by a gin drunk! (8)
I believe the answer is:
campaign
'drive' is the definition.
('campaign' can be a synonym of 'drive')
'affected by a gin drunk' is the wordplay.
'affected' becomes 'camp' (I've seen this before).
'by' is a charade indicator (letters next to each other).
'drunk' indicates anagramming the letters.
'gin' with letters rearranged gives 'ign'.
'camp'+'a'+'ign'='CAMPAIGN'
(Other definitions for campaign that I've seen before include "Series of activities to attain a goal" , "lobby" , "A series of planned activities, as for advertising" , "Co-ordinated activities for a purpose" , "electioneering" .)