A word used to describe a negative consequence that someone has earned through previous bad behavior of some kind, an event that feels to others like just what the person deserved. For example, Roger Ebert's review of Gone With The Wind describes the ending as "Scarlett gets her comeuppance at last."

Just deserts, well-deserved punishment for past transgressions.

Although the term originated in the mid-19th century, it was made popular because of its promiment use in Orson Welles' film The Magnificent Ambersons. So popular in fact, that it became standard to use the word in correlation to the original Booth Tarkington novel the movie is based on. Actually the word was Welles' own addition and is never mentioned in the novel.