Afghan
Afghan (Pashto/Persian: افغان) refers to someone from Afghanistan. Prior to the establishment of the modern country of Afghanistan, Afghan was used to refer to a member of the Pashtuns.
The earliest mention of the name Afghan (Abgân) is by Shapur I of the Sassanid Empire during the 3rd century CE. In the 4th century the word "Afghans/Afghana" (αβγανανο) as reference to a particular people is mentioned in the Bactrian documents.
As an adjective, the word Afghan also means "of or relating to Afghanistan or its people, language or culture". There are political disputes regarding this: there are members of the non-Pashtun ethnicities of Afghanistan that reject the term Afghan being applied to them, and there are Pashtuns in Pakistan that wish to have the term Afghan applied to them.