A proper adjective is a adjective derived from a proper noun. Some examples of proper adjectives to describe the common noun man are:
Manx is the proper adjective for the Isle of Man.
No, it's a proper noun. Adjectives describe nouns. E.g. in 'Matthew is a happy man', happy is an adjective.
The proper adjective for southwest is "southwestern."
The proper adjective is Haitian.
The proper adjective for Portuguese is "Portuguese."
Vietnamese is the proper adjective for Vietnam.
The proper adjective for George is Georgian.
The proper adjective for Siam is Siamese.
Mayan is itself a proper adjective.
Freudian is the proper adjective for Freud.
The proper adjective for Georgia is Georgian.
No, old is not a proper adjective. A proper adjective is an adjective derived from a proper noun, such as Swiss cheese, Bolivian pottery, Chinese silk, etc.