to polish or make something smooth; or to look carefully at something, scrutinizing it (see Molina)
IPAspelling:
iːʃpetsoɑː
Alonso de Molina:
ixpetzoa. nitla. (pret. onitlaixpetzo.) acepillar o bruñir o alisar algo.
ixpetzoa. nin. (pret. oninixpetzo.) mirar con diligencia escudriñando alguna cosa. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 46v. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
ĪXPETZOĀ vrefl, vt to be involved in scrutinizing something; to plane, smooth, polish something / mirar con diligencia escudriñando alguna cosa (M), acepillar o bruñir o alisar algo (M) [(3)Tp.217]. See ĪX-TLI, PETZOĀ. Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 117.