pepetlaca.

Headword: 
pepetlaca.
Principal English Translation: 

to shine or shimmer (see Molina); to reflect light, to be resplendent (see Karttunen)

IPAspelling: 
pepetɬɑkɑ
Alonso de Molina: 

pepetlaca. ni. (pret. onipepetlacac.) resplandecer o relumbrar.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 80v. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

PEPETLACA to shimmer, to reflect light, to be resplendent / resplandecer o relumbrar (M) R has this with a glottal stop in the first syllable, but there should not be one, and C, T, and Z agree on this. See PETLĀN(I).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 191.

Attestations from sources in English: 

pepetlaca (verb) = to shine, to glitter
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1877), 160.

yuhqui in Tonatiuh ic pepetlaca, inic motetlanextilia = He is like the sun, the way he shimmers, the way he shines on people (late seventeenth century, Central Mexico)
Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 39.