Direction/Location:
* Eastern: relating to the east
* Western: relating to the west
* Northern: relating to the north
* Southern: relating to the south
* Midwestern: relating to the middle of the west
* Northeastern: relating to the northeast
* Southeastern: relating to the southeast
* Northwestern: relating to the northwest
* Southwestern: relating to the southwest
Other:
* Astern: at or towards the stern of a ship
* Stern: strict or severe in manner
* Extern: someone who is not a member of a particular group
* Intern: a student or trainee who works in a professional setting
* Modern: relating to the present time
* Ancient: relating to the past, especially a long time ago
Note: Some words like "satern" and "batern" are archaic and rarely used today.
You can use "-ern" to form new adjectives related to specific locations, like "Mountaineern" for someone who lives in the mountains.