A show trial or a show court is a trial where the outcome is already decided before the trial starts. The purpose of the trial is often for it to be used as propaganda, often in order to try to convince the general public of the guilt of the accused. Other purposes may include revenge against the accused and/or for the public punishment to be a warning to others.
Related types of trials
A "kangaroo trial" or a "kangaroo court" may be a show trial and/or a trial that lacks proper legal authority. They are typically associated with groups that practice their own brand of justice, which is outside of the formal judicial process. See also lynching.
A "mock trial" or a "moot court" is a simulated trial, not claiming to be legally valid, such as for practice by law students. Some may be considered to be show trials, not claiming to be legally valid, but still used for propaganda purposes, such as propaganda mock trials accusing disliked groups and countries of war crimes.