What does to cry sour grapes mean?

The phrase "sour grapes" is used to describe a situation where someone belittles or criticizes something they want but cannot have, to make themselves feel better. It suggests that the criticism or negative attitude comes from a sense of envy or disappointment rather than a genuine evaluation. The phrase is often used in a proverb: "Grapes are sour when they're out of reach" or "Sour grapes are for the foxes". It's a saying that teaches a moral about not being envious or bitter about things that are not achievable or obtainable.