President's instinct at the end — no moral code (7)
I believe the answer is:
bushido
'moral code' is the definition.
(moral code of samurais)
'president's instinct at the end no' is the wordplay.
'president' becomes 'bush' (I've seen this in other clues**).
'instinct' becomes 'id' (id is a kind of instinct).
'at the end' indicates one should take the final letters.
The final letter of 'no' is 'o'.
'bush'+'id'+'o'='BUSHIDO'
(Other definitions for bushido that I've seen before include "chivalric code" , "honourable code" , "Strict ethical code of Japanese samurai" , "code out east" , "Feudal code of the Samurai" .)