to make something dull, or to remove the point off something (see Molina)
IPAspelling:
jɑkɑkotoːnɑ
Alonso de Molina:
yacacotona. nitla. (pret. onitlayacacoton.) despuntar algo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 30r. col. 1. Thanks to Joe Campbell for providing the transcription.