Bar reduced expenditure on whiskey (6)
I believe the answer is:
outlaw
'bar' is the definition.
(I've seen this before)
'reduced expenditure on whiskey' is the wordplay.
'reduced' means to remove the last letter.
'expenditure' becomes 'outlay' (the cost of setting something up).
'on' is a charade indicator (letters next to each other).
'whiskey' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'outlay' with its final letter taken off is 'outla'.
'outla'+'w'='OUTLAW'
(Other definitions for outlaw that I've seen before include "Ban - bandit" , "Embargo" , "Irish Tory" , "Robin Hood, for example" , "A fugitive from legal justice" .)