Although the words can be considered synonyms, there is a distinction:
- morals are beliefs based on practices or teachings regarding how people conduct themselves in personal relationships and in society,
- while ethics refers to a set or system of principles, or a philosophy or theory behind them. (Principles, however, is itself a synonym for morals.)
One lives according to one’s morals but adheres to one’s ethics while doing so. Morals are the tools by which one lives, and ethics constitute the manual that codifies them. Source