to become hardened and obstinate in bad things (see Molina)
Orthographic Variants:
yollotlaquactia
Alonso de Molina:
yollotlaquactia. ni. (pret. oniyollo tlaquactiac.) endurecerse y obstinarse enel mal. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 40v. col. 2. Thanks to Joe Campbell for providing the transcription.