to lower one's eyes, to look at the ground (given in the first person; see Molina)
Alonso de Molina:
tlalchi nitlachia. (pret. tlalchi onitlachix.) abaxar los ojos, mirando hazia el suelo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 123v. col. 2. Thanks to Joe Campbell for providing the transcription.