A method by which an act can be labeled "right" or "wrong" or "neither". Many moral philosophies exist.
Egoism: "Drinking is wrong because it is bad for me."
Hedonism: "Drinking is right because it makes me feel good."
Utilitarianism: "Drinking is right because it brings about more good than evil."
Libertarianism: "Drinking is not wrong since it does not infringe on anyone elses liberty. It is not right since I am also at liberty to NOT drink."
Divine Command Theory: "Let's burn witches! the Bible says we should."
Christian morality requires that you kill your disobedient children.