Principled (7)
I believe the answer is:
ethical
'principled' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ethical that I've seen before include "Relating to morals" , "Morally correct, in accordance with professional standards" , "Conforming to accepted standards of behaviour" , "Abiding by moral principles" , "Moral, honest" .)