An adjective goes right in front of a noun to describe the noun. A proper adjective is a describing word that gets made from a proper noun. We always capitalize a proper adjective.
These proper nouns are the names of places or people. Notice that they are capitalized.
Mexico, America, Germany, Africa, France, Luther, Christ
We can change each of these proper nouns into a proper adjective. Look at these proper adjectives:
Mexican, American, German, African, French, Lutheran, Christian
These proper adjectives are capitalized just like the proper nouns, but they are spelled a little differently.
Here’s how we use proper adjectives in a sentence:
While I was in Mexico, I enjoyed Mexican food.
A citizen of America usually has an American passport.
For dinner in France, I ate French fries.
Martin Luther had certain beliefs that are practiced in the Lutheran church.
I am learning the German language because I am traveling to Germany next summer.
A proper adjective is formed from a proper noun. A proper adjective is always capitalized and goes right in front of a noun to modify the noun.