'arkansan' originates from English, specifically the word 'Arkansas' with the adjectival/demonymic suffix '-an', where 'Arkansas' came into English from French (as 'Arkansas') ultimately representing a native Siouan/Quapaw name for the people or place.

'arkansan' was formed in English by attaching the suffix '-an' to 'Arkansas' to create a demonym. 'Arkansas' itself entered English via French from an Algonquian/Siouan native word that referred to the local people or river region, and over time the spelling and pronunciation stabilized to the modern forms 'Arkansas' and 'Arkansan'.

Originally tied directly to the place name and its people, the form came to mean specifically 'a person from Arkansas' or 'relating to Arkansas' and retains that demonymic/attributive meaning today.