Purchaser with no cash is more virtuous (5)
I believe the answer is:
purer
'more virtuous' is the definition.
('pure' can be a synonym of 'virtuous')
'purchaser with no cash' is the wordplay.
'with no' is a deletion indicator.
'purchaser' with 'cash' taken out is 'PURER'.
'is' acts as a link.
(Other definitions for purer that I've seen before include "Less adulterated" , "more clean" , "Less immoral" , "cleaner" , "More chaste" .)