an interjection used to object to something or complain
Alonso de Molina:
axax. ay ay. interjection. del que se quexa. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 9v. col. 2. Thanks to Joe Campbell for providing the transcription.