neyoliximachiliztli.

Headword: 
neyoliximachiliztli.
Principal English Translation: 

conscience (literally, the knowledge of what is in one's heart)

IPAspelling: 
nejoːliːʃimɑtʃilistɬi
Alonso de Molina: 

neyoliximachiliztli. consciencia.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 66r. col. 1. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

toyollomachiliz in toneyoliximachiliz in toconsciencia = our conscience;
neyoliximachiliztli = conscience
Susanne Klaus, Uprooted Christianity: The Preaching of the Christian Doctrine in Mexico, Based on Franciscan Sermons of the 16th Century Written in Nahuatl (Bonn: Bonner Amerikanistische Studien e. V. c/o Seminar für Völkerkunde, Universität Bonn, 1999), 249, 251.