Mercy or leniency (8)
I believe the answer is:
clemency
This clue is a double definition.
'mercy' is the first definition.
(I know that mercy can be written as clemency)
'leniency' is the second definition.
(I know that clemency is a type of leniency)
(Other definitions for clemency that I've seen before include "The quality of mercy" , "Quality of being merciful" , "Mercifulness" , "Mercy or charity" , "Leniency and compassion towards offenders" .)