Northern is a common word used to describe something located or originating from the northern part of a region, country, or planet. However, there are several synonyms for the word that can be used to vary your language and prevent repetitiveness. Some options include "arctic" when referring to the northernmost points of the globe, "boreal" for regions characterized by coniferous forests, "northerly" for movement in the northern direction, and "polar" when discussing the topmost regions of the planet. Additionally, "frigid" and "chilly" can be used to describe the climate of northern areas. By incorporating synonyms for northern into your writing, you can add more depth and variation to your language.