A person or thing that is good is satisfying, pleasant, or useful. A good experience or result; the good news from the doctor. Good is also a noun that means:

A kind, fair, or honest person; the good man. Good is also a euphemism for God.

To make good on a promise or obligation. To be or act in a responsible manner. To be in the best interests of someone or something. “It is in my best interests to be as discreet as possible about the affair.” —Alfred North Whitehead, “Problems of Philosophy” (1924). To make up for something. “He made good on his promises” —John Dryden, “Anna Maria” (1747). To be fit, suitable, or sufficient for a purpose. “A good house, a car, and a job” —William Shakespeare, “Much Ado About Nothing” (1622).

In the history of ethics, there have been many discussions about what is morally right or just. However, discussion of the notion of good really began to take off in 1903 when G. E. Moore published his Principia Ethica. His article brought up the question of whether it was possible to present an analysis of goodness rather than simply presenting conceptions of it.

Moore argued that it was not possible. He criticized several philosophers who had attempted to do so and claimed that they committed what he called the naturalistic fallacy. The fact that one can always ask “but is x good?” shows that their analyses of goodness were flawed.

Franz Brentano developed an analysis of good that occupied a sort of halfway point between Moore and naturalism. His theory was based on the idea that goodness is a nonnatural property that can be discerned through certain kinds of pro-attitudes. It was not an unqualified success, though, and his key concept, the notion of fittingness, never received a satisfactory explication.

Today almost everyone agrees that good is a predicate adjective, like better and well, and that it can be used as an adjective after feelings. However, an old notion that good should be reserved for virtues still occasionally appears in print. Generally, people say “I feel good,” not “I feel well.” In the Bible, it is often transcribed as Kosmios or kosmos. It is probably related to the Latin word genus, meaning ‘kind’ or “beneficial.” Compare Old English eod, Middle English god, and German gut, from Proto-Germanic *ghedh-, *ghodh- (“to unite, be associated, suit”). Also compare Scots guid, Dutch goed, Danish godt, Swedish god, Albanian dial. guodas, and Sanskrit gdy. Also see benevolent, obedient, and true.