Definition from Nolo’s Plain-English Law Dictionary
Proceedings of any court or other government body that are held in secret and produce arbitrary results. This derogatory term takes its name from an English court, whose members were appointed by the crown, that met in the 15th to 17th centuries. That court, which met in a room that was apparently decorated with gilt stars, decided guilt and punishment of people accused of violating the monarch's orders. Its practices made "star chamber" synonymous with any unfair and secretive proceedings.