Tapatío is a Mexican Spanish colloquial term for someone from Guadalajara in the state of Jalisco, Mexico's second largest city. It is also used as an adjective for anything associated with Guadalajara.
Etymology
The word derives from the Nahuatl word tapatiotl, the name of a monetary unit in pre-Columbian times which became most closely associated with the region in which today's Guadalajara is situated.
References
Tapatío Wikipedia(Text) CC BY-SA