Principal English Translation: 

pejorative term for Spaniard, European (see Karttunen)

Orthographic Variants: 
cachopīn, cachupin, cachopopin, gachupin
Frances Karttunen: 

CACHOPĪN pl: -TIN pejorative term for Spaniard, European / gachupín (T) [(1)Tp.112]. This is thought to be a Nahuatl word derived from CAC-TLI ‘shoe’ and CHOPĪNĪA ‘to pick at something,’ but this /K019/ attestation is in a modern source, where it could be a loanword or a back loan. The term appears as early as the first half of the 18th century in Nahuatl texts. [Since Frances Karttunen wrote this, it has been found in earlier Nahuatl texts; see attestations.]
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 20.

Attestations from sources in English: 

Cachopopin [probably with the extra syllable as an error] is attested in seventeenth-century annals. Townsend points out that it may have been a translation back from the Spanish, gachupín.
Camilla Townsend, Here in this Year: Seventeenth-century Nahuatl Annals of the Tlaxcala-Puebla Valley (Stanford: Stanford University Press, 2010), 51 and 152, note 3.

Cachopin is translated in a late eighteenth-century dictionary as: "a name by which the Indians of Mexico call an European."
Diccionario Espanol e Ingles (London: Piestre, 1786), 126.

The seventeenth century Casas Cachupines of New Mexico—and the Velez Cachupín family living there in the eighteenth century—may coincide with a mention in Cervantes' Don Quixote to the Cachopin (or Cachupin) family.
Malcolm Ebright and Rick Hendricks, The Witches of Abiquiu: The Governor, the Priest, the Genízaro Indians, and the Devil (Albuquerque: University of New Mexico Press, 2006), 67–68.

Don Tomás Velez Cachupín became an official entrusted with Viceroy Juan Francisco de Güemes' stables in 1746 and was interim governor of New Mexico in 1749.
Malcolm Ebright, Advocates for the Oppressed: Hispanos, Indians, Genízaros, and Their Land in New Mexico (Albuquerque: University of New Mexico Press, 2014), 195.

See also: