a book seller (see Molina); this combines the root for amoxtli (books) with namaca (to sell)
Alonso de Molina:
amoxnamacac. vendedor de libros. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 5v. col. 2. Thanks to Joe Campbell for providing the transcription.