含冤

Literary / news register — you'll see it in headlines about wrongful convictions ('含冤25年，他终获无罪判决'), historical writing about purges, and ghost stories where the dead 含冤而死 ('died bearing an injustice') and become haunting spirits. Compare with the milder 委屈 (wěiqu, 'feel wronged'), which is for everyday 'unfairness' rather than legal injustice.

含 ('to hold in the mouth') + 冤 ('grievance') — to be holding an injustice silently inside, unable to spit it out. The image fits classical Chinese trope: the wronged ghost who returns demanding 申冤 ('to seek redress').