The proper adjective for Siam is Siamese.
Chinese is the adjective form of the proper noun China. For other uses, 'Sinic' is the word you're looking for, as in "Sinic customs are different from those of Japan". The prefix derived from that is 'sino' as in the phrase "Sino-Indian border".
The proper adjective for George is Georgian.
The proper adjective for Antigua is Antiganantigan
Kuwaiti is the proper adjective for Kuwait.
A proper adjective is a descriptive word derived from a proper noun.Some examples are:Asia (proper noun) - Asian (proper adjective)Brazil (proper noun) - Brazilian (proper adjective)Canada (proper noun) - Canadian (proper adjective)Elizabeth I (proper noun) - Elizabethan (proper adjective)Sigmund Freud (proper noun) - Freudian (proper adjective)George Orwell (proper noun) - Orwellian (proper adjective)Proper nouns and proper adjectives are always capitalized.
Thai
The proper adjective for the word Thailand is Thai. Example: Because I am from Thailand, I am Thai.
Chinese is the adjective form of the proper noun China. For other uses, 'Sinic' is the word you're looking for, as in "Sinic customs are different from those of Japan". The prefix derived from that is 'sino' as in the phrase "Sino-Indian border".
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.
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.