A more thorough explanation:

forinsecus

Forinsecus means "on the outside" in history. It can also refer to a foreigner or someone from another jurisdiction.

• The castle walls were fortified to keep forinsecus invaders out.
• The court could not prosecute the forinsecus suspect without the help of the neighboring jurisdiction.

The first example shows how forinsecus is used to describe something outside of a specific area. The castle walls were built to keep people who were not from the area out. The second example shows how forinsecus can also refer to someone from another jurisdiction. The court needed help from another jurisdiction to prosecute the suspect because they were not from the same area.