That which is good is morally correct, excellent, and virtuous. Ultimately, God is the standard of what is good since it is His nature. In one sense, goodness is relative in that it is good to return a wallet--good to be honest. On the human level, this is good. Compared to God, however, all of man's efforts are not good, and no one does good (Rom. 3:10-12).
That which is good is debated. However, normally it is considered to be a favorable result, action, or intention. That which is good can be the desired effect for which an action was intended. Good can refer to something that has a better quality, appearance, skill, etc. Moral goodness is more problematic in that intentions can be bad, but the results not bad. Was the action then good? Is good derived from human preferences or divine revelation?