Moral code that could be his, etc (6)
I believe the answer is:
ethics
'moral code' is the definition.
'could be his etc' is the wordplay.
'could be' indicates anagramming the letters.
'his'+'etc'='hisetc'
'hisetc' anagrammed gives 'ETHICS'.
'that' is the link.
(Other definitions for ethics that I've seen before include "Code of integrity in business" , "Code of behaviour" , "Set of business principles" , "Principles of right and wrong" , "Codes of conduct in business affairs" .)