tzoniztaya.

Headword: 
tzoniztaya.
Principal English Translation: 

for one's hair to be or turn white

James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 240.

IPAspelling: 
tsonistɑjɑ
Alonso de Molina: 

tzoniztaya. ni. (pret. onitzoniztayac.) encanecer.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 153v. col. 1. Thanks to Joe Campbell for providing the transcription.

Lockhart’s Nahuatl as Written: 

ni. Class 1 or 2: ōnitzoniztayac or ōnitzoniztaz.
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 240.