Peruvian is the proper adjective for Peru. Example: My Peruvian cousin only visits sometimes because where I live is far from her native country of Peru.
Peruvian is the proper adjective related to Peru. For instance: Some Peruvian customs were strongly influenced by the mountainous locations.
The proper adjectives are:KoreanPolishAlaskanBelgianSwedishFrenchRussianCubanPeruvianIndian
Large and varied are both adjectives. South would be an adjective if it were not part of a proper noun. Amazon is likely a noun adjunct here, but Amazonian would be a proper adjective.
Cuban and Peruvian are the proper adjectives for Cuba and Peru.
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 George is Georgian.
The proper adjective for Georgia is Georgian.
The proper adjective for Mayan is "Mayan."
Freudian is the proper adjective for Freud.