In most cases, east is a noun, one of the cardinal directions. North, East, South, West. The East has countries such as China, Japan and Russia. Eastern is always an adjective. The eastern coast of the country. Eastern (Oriental) food. However, east can sometimes be an adjective as well. East Sussex, East Texas, East Wind Finally, east can also be an adverb, and this, along with the noun is usually the most common form. He is going east towards the desert. Go east. Most of this applies to the other directions as well.

Hi! You might want to take a look at this: https://dictionary.cambridge.org/grammar/british-grammar/east-or-eastern-north-or-northern I have found it very helpful!

East: 1. Noun. The east is opposite the west. This noun combines with other nouns to make compounds: The east coast; East-side 2. adverb of direction: go east, walk east, etc Eastern: adjective - eastern traditions; eastern cuisine; eastern culture;...