Border sheep raised on alcoholic drink (6)
I believe the answer is:
margin
'border' is the definition.
(I know that border can be written as margin)
'sheep raised on alcoholic drink' is the wordplay.
'sheep' becomes 'ram' (male sheep).
'raised' shows that the letters should be reversed in order (going up in a down clue).
'on' is a charade indicator (letters next to each other).
'alcoholic drink' becomes 'gin' (gin is an alcoholic spirit).
'ram' back-to-front is 'mar'.
'mar'+'gin'='MARGIN'
(Other definitions for margin that I've seen before include "Space at edge of page" , "Periphery" , "Edge; room for error" , "Boundary line or the area" , "Bland space around text" .)