Ethics refers to the study of what we understand to be good and right behavior and how people make those judgments
Other /More definition:
Ethics is defined as the study of what people understand to be good and right behavior and how people make those judgments. It is teh study of proper action.
Ethics generally describes the collectively agreed upon "correct" behaviors within the context of a professional group; the practical normative study of the rightness and wrongness of human conduct; principles of conduct founded on a society's moral code.