one who does not understand or hear; someone who is incorrigible (see Molina)
Alonso de Molina:
atlacaqui. el que no entiende ni oye, o el incorregible. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 8r. col. 1. Thanks to Joe Campbell for providing the transcription.