tepitzaui. (pret. otepitzauh.) endurecerse alguna cosa. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 103r. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
TEPĪTZAHU(I) for something to become tough, hardened / endurecerse alguna cosa (M) [(1)Tp.225). See TEPĪTZOĀ. Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 230.