tzayani.

Headword: 
tzayani.
Principal English Translation: 

for the heart to break; for something to tear or break (see Molina and Karttunen)

Orthographic Variants: 
tzaiani
IPAspelling: 
tsɑyɑːni
Alonso de Molina: 

tzayani. rasgarse algo desta manera.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 151v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

TZAYĀN(I) for something to tear / rasgarse algo (M) [(1)Cf.75r, (1)Tp.243]. See TZAYĀN(A).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 311.

Attestations from sources in English: 

neyoltzayanalizpahtli = medicine for the breaking of the heart (central Mexico, sixteenth century)
Louise M. Burkhart, Holy Wednesday: A Nahua Drama from Early Colonial Mexico (Philadelphia: University of Pennsylvania Press, 1996), 180.

tzaiani = it is ripped, it breaks; they break open (speaking of the lips becoming cracked and chapped) (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 97, 132.