A controversy already judicially decided is said to be:

The term that describes a controversy that has already been judicially decided is "res judicata." This Latin phrase translates to "the matter has been adjudicated." It refers to the principle that once a court has rendered a final judgment on a case, the same parties cannot relitigate the same issue in future proceedings. This principle serves to promote the finality of judgments, prevent judicial inconsistency, and protect parties from the burden of being called to defend against the same claim multiple times.

The other terms provided are related but describe different concepts. "Ipse dixit" refers to a statement made by someone in a position of authority that is taken as true without proof. "Res nova" means a new matter or situation that has not been previously addressed or ruled upon in court. "Sui generis" refers to something unique or of its own kind, which does not fit into a standard category. These terms do not capture the essence of a matter that has been conclusively settled by the court.