Arabian.
Before modern-day Saudi Arabia was founded, the area is called Al-Hijaz. When Abdullah ibn Saud conquered the area, he named it after himself.
The proper adjective for Portuguese is "Portuguese."
The proper adjective for Mayan is "Mayan."
The proper adjective for Russian is "Russian."
The proper adjective for Mexican is "Mexican."
A common adjective describes a general characteristic of a noun, while a proper adjective is derived from a proper noun and specifically identifies a particular noun. For example, "blue" is a common adjective, while "Italian" is a proper adjective derived from the proper noun "Italy."
A proper adjective is an adjective formed from a proper noun. "Arabian", "Grecian", "Japanese", "African".
The word 'Arabian' is the proper adjective form of the proper noun Arabia.
The proper adjective for Portuguese is "Portuguese."
The proper adjective for southwest is "southwestern."
The proper adjective for Haiti is Haitian.
Vietnamese is the proper adjective for Vietnam.
The proper adjective for Siam is Siamese.
The proper adjective for Georgia is Georgian.
The proper adjective for Mayan is "Mayan."
The proper adjective for George is Georgian.
Freudian is the proper adjective for Freud.
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.