to become obscured by shade or darkness (see Molina)
IPAspelling:
miʃtekomɑktiɑ
Alonso de Molina:
mixtecomactia. ni. lo mesmo es que mixtecmacti Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 57r. col. 2. Thanks to Joe Campbell for providing the transcription.