Saintliness (5)
I believe the answer is:
piety
'saintliness' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for piety that I've seen before include "Dutiful devotion" , "An unthinkingly accepted belief" , "Attentive religious practice" , "Godly behaviour" , "Holiness" .)