to come to know something completely (the root verb is açi) (see Molina and Karttunen)
IPAspelling:
ɑhʃiliɑː
Alonso de Molina:
axilia. nic. (pret. onicaxili.) alcanzar asaber algo enteramente. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 10r. col. 1. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
AHXILIĀ vt to get to know something entirely / alcanzar a saber algo enteramente (M) applic. AHCI Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 9.