Kind, merciful (6)
I believe the answer is:
humane
I believe this is a double definition.
'kind' is the first definition.
(similar in meaning)
'merciful' is the second definition.
(similar in meaning)
(Other definitions for humane that I've seen before include "Characterised by kindness" , "Compassionate, merciful" , "Compassionate, benevolent" , "Kind-hearted and compassionate" , "Kind and merciful" .)