What are the proper adjectives for Rome, Alaska, and Norway?
He was a Roman senator. In this sentence, Roman (referring to someone from Rome) describes the senator. He is not an American senator, he is a Roman senator
She was an Alaskan representative. She is a representative from Alaska.
They were Norwegian citizens. They are citizens of Norway.
Proper adjectives are related to and derived from proper nouns. Places, such as Azerbaijan, are proper nouns. Their corresponding proper adjectives are used to describe people/things of that place.
Other proper adjectives:
Victorian/Elizabethan (Victorian/Elizabethan era/age, relating to Queen Victoria and Queen Elizabeth I of England, others include Georgian era and Edwardian era)
Shakespearean (Shakespearean actors, for example)
Twix (Twix bars, where bars is a noun and Twix is describing it, Twix is a brand)