I was asked to define good. Well, what it isn't is those who claim that it's god. The history of religion is enough evidence to support this claim.

Inside the human brain, there exists the potential for survival which is actually doing
less harm and more helpful actions to others. "Good" is the realization that how you treat others is important and the better you treat people around you, the better chance our species has for survival. Stopping wars would be a good first step to achieving a kind of "good" for humanity. The antonym, of course, is "bad" which can be defined as the actions of those who look out for themselves at the expense of other's needs.

Franz de Waal in his book, "The Age of Empathy" suggests that because of his scientific study of primate behavior, working together to build common interests, being empathetic and sympathetic to others is possibly built into our DNA. That's one meaningful definition of good.

This is not a requirement for most religions. If it were, you'd have more enlightened behavior from religious people.