Moral principles (6)
'moral principles' is the definition.
('ethic' can be a synonym of 'moral principle')
This is all the clue.
(Other definitions for ethics that I've seen before include "Moral principles in middle" , "Standards to be observed as in business" , "Science of morals" , "Codes or principles for professional people" , "Professional codes of behaviour.18 Serious or heartfelt" .)
'moral principles' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for scruples that I've seen before include "Qualms" , "Feelings of doubt based on conscience" , "Doubts or hesitations promted by conscience" , "Feelings of doubt arising from conscience" , "Doubts stemming from conscience or principles" .)