The Bedford Glossary of Critical and Literary Terms - Ross Murfin 2018
Poetic justice: The idea that virtuous and evil actions are ultimately dealt with justly, with virtue rewarded and evil punished. Poetic justice occurs, for instance, when a misunderstood protagonist is praised after a long struggle or when his or her antagonist is cast out from the community.
The term was coined by Thomas Rymer, an English literary critic and historiographer who viewed poetic justice as a didactic device conducive to furthering morality and used it specifically with reference to poetic works, including dramas, in Tragedies of the Last Age Consider’d (1678). Today, the term is used with reference to all types of literary works — as well as life in general — and is often applied specifically to situations in which the hero and villain get their “just deserts” at a pivotal moment for both of them, as when the villain is shot while trying to shoot the hero. Furthermore, contemporary critics almost uniformly reject Rymer’s view that literature should provide moral instruction.
EXAMPLES: In Charles Dickens’s Oliver Twist (1837), when villain Bill Sykes envisions the eyes of Nancy, the girlfriend he has viciously murdered, he accidentally hangs himself by a rope he had intended to use to escape from an angry crowd seeking vengeance for her death.
The movie The Departed (2006) closes with a shocking scene of poetic justice, as Sgt. Colin Sullivan is shot in his own home by a fellow sergeant, just as it seems that Sullivan has escaped detection as the mole in the police force responsible for the deaths of several officers.