Morals alter with social agreement. Laws are created to enforce morals. It is stated in the dictionary that ethics and morals are interchangeable, but these words do have a variation. Ethics has a bigger meaning, of what is ideal and survival, not just what is socially agreed on or acceptable.
Gentleman has an innate understanding of what is correct and wrong. Correct can be witnessed as simply just what is survival for gentleman. For instance, we usually agree it is not survival