Longman Dictionary of Contemporary English
Wiktionary
n. An error at a trial which led to an unjust outcome, such as the conviction of a person for a crime they did not commit.
Wikipedia
A miscarriage of justice primarily is the conviction and punishment of a person for a crime they did not commit. The term can also apply to errors in the other direction—" errors of impunity", and to civil cases. Most criminal justice systems have some means to overturn, or "quash", a wrongful conviction, but this is often difficult to achieve. In some instances a wrongful conviction is not overturned for several years, or until after the innocent person has been executed, released from custody, or has died.
"Miscarriage of justice" is sometimes synonymous with wrongful conviction, referring to a conviction reached in an unfair or disputed trial. Wrongful convictions are frequently cited by death penalty opponents as cause to eliminate death penalties to avoid executing innocent persons. In recent years, DNA evidence has been used to clear many people falsely convicted.
The Scandinavian languages (viz. Danish, Norwegian and Swedish) have a word, the Swedish variant of which is justitiemord, which literally translates as "justice murder." The term exists in several languages and was originally used for cases where the accused was convicted, executed, and later cleared after death. While a miscarriage of justice is a Type I error for falsely identifying culpability, an error of impunity would be a Type II error of failing to find a culpable person guilty. However, the term "miscarriage of justice" is often used to describe the latter type as well.
With capital punishment decreasing, the expression has acquired an extended meaning, namely any conviction for a crime not committed by the convicted. The retention of the term "murder" represents both universal abhorrence against wrongful convictions and awareness of how destructive wrongful convictions are. Some Slavic languages have also the word (justičná vražda in Slovak, justiční vražda in Czech) which literally translates as "justice murder", but it is used for Judicial murder, while miscarriage of justice is "justiční omyl" in Czech, implying an error of the justice system, not a deliberate manipulation.
Also, the term is sometimes used for a gross, deliberate miscarriage of justice. Show trials (not in the sense of high publicity, but in the sense of lack of regard to the actual legal procedure and fairness), due to their character, often lead to such travesties.
The concept of miscarriage of justice has important implications for standard of review, in that an appellate court will often only exercise its discretion to correct plain error when a miscarriage of justice (or "manifest injustice") would otherwise occur.
Usage examples of "miscarriage of justice".
But when something like this happens, that loyalty can cause a miscarriage of justice.
And so a tragic and irrevocable miscarriage of justice was happily averted.
If Trisu is punished while protesting his innocence and flourishing his proof of forgery, then his fellow lords will blame his liege and the King for a miscarriage of justice.
He now perceived that there was likely to be a miscarriage of justice here, and he rose to the occaslon.
But I've never felt it was a gross miscarriage of justice, either.
Except for the fact that the trick served to prevent a serious miscarriage of justice, I would certainly hold attorney for the Defense in contempt.
It is also unusual in that it employs the device of the possible miscarriage of justice….
One cause is the fact that in early youth a miscarriage of justice gave him several years in prison, an experience which cast a stigma on his name and which made it impossible for him, for many years after, to obtain honest employment.