to be made angry a lot (see Molina)
yolpozoni. ni. (pret. oniyolpozon.) enojarse mucho assi. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 41r. col. 2. Thanks to Joe Campbell for providing the transcription.