Old writers point to outlay (7)
I believe the answer is:
expense
'outlay' is the definition.
('expense' can be a synonym of 'outlay')
'old writers point' is the wordplay.
'old' becomes 'ex'.
'writers' becomes 'pens' (I've seen this before).
'point' becomes 'e' (E is an example).
'ex'+'pens'+'e'='EXPENSE'
'to' is the link.
(Other definitions for expense that I've seen before include "Disbursal" , "Disbursement" , "Cost - price" , "damage" , "Outlay or cost" .)