Code cracked with right doctrine (5)
I believe the answer is:
credo
'doctrine' is the definition.
(I know that credo is a type of doctrine)
'code cracked with right' is the wordplay.
'cracked with' is an anagram indicator.
'right' becomes 'r' (common abbreviation).
'code' anagrammed with 'r' gives 'CREDO'.
(Other definitions for credo that I've seen before include "Mass movement" , "set of ideas" , "Set of principles" , "Formal statement of beliefs" , "One's system of beliefs" .)