Spoil drink for profit (6)
I believe the answer is:
margin
'profit' is the definition.
(margin is a kind of profit)
'spoil drink' is the wordplay.
'spoil' becomes 'mar' (I've seen this before).
'drink' becomes 'gin' (gin is a kind of drink**).
'mar'+'gin'='MARGIN'
'for' acts as a link.
(Other definitions for margin that I've seen before include "Blank space around a page" , "Blank space that surrounds the text on a page" , "Boundary line or the area" , "Border or leeway" , "Permissible difference" .)