Other types of nouns are proper nouns (or real nouns).
Real nouns start with a capital letter: Spain, Brad, and Pizza Hut.
What are proper adjectives?
This is the same with adjectives.
Most adjectives are common adjectives: slow, modern, red, and exciting.
Proper adjectives start with a capital letter: Spanish, Martian, and Russian.
Proper adjectives are usually derived (formed) from proper nouns.
Spain = Spanish
Mars = Martian