cauallo pixqui.

(a loanword from Spanish)

cauallo pixqui.
Principal English Translation: 

groomsman, who works with horses; a horse keeper (see Molina)
(partially a loanword from Spanish; caballo, horse); also seen translated as arriero, muleteer

Orthographic Variants: 
caballo pixqui
Alonso de Molina: 

cauallo pixqui. cauallerizo.
.Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 12v. col. 2. Thanks to Joe Campbell for providing the transcription.