What does good grief mean?

The phrase "good grief" is an exclamation that expresses surprise, annoyance, or disappointment. It is often used in a humorous way to make light of a situation that is not particularly serious. For example, someone might say "good grief" if they trip and fall, or if they lose their keys. The phrase can also be used more seriously to express genuine grief or sorrow, such as when someone has lost a loved one. In this context, "good grief" might be used to mean "deep grief" or "profound sorrow".