Fine to leave rich drunk (4)
I believe the answer is:
lush
'drunk' is the definition.
(lush is a kind of drunk)
'fine to leave rich' is the wordplay.
'fine' becomes 'f' (abbreviation).
'to leave' is a deletion indicator.
'rich' becomes 'flush' ('flush' can be similar in meaning to 'rich').
'flush' with 'f' taken out is 'LUSH'.
(Other definitions for lush that I've seen before include "Verdant" , "Of grass, growing thick and strong" , "Lavish - boozer" , "Luxuriant - drunkard (slang)" , "one wants a lot to drink" .)