ahuiac.

Headword: 
ahuiac.
Principal English Translation: 

something smooth and fragrant, something pleasant, pleasing

Orthographic Variants: 
auiac, auiyac, ahuiyac
IPAspelling: 
ɑhwiɑːk
Alonso de Molina: 

auiac. cosa suaue y olorosa, o cosa gustosa.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 9v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

AHHUIĀC something fragrant / cosa suave y olorosa, o cosa gustosa (M) See AHHUIĀYA.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 6.

Attestations from sources in English: 

ahuiac (adjective) = agreeable, pleasant, sweet
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1887), 149.

ipampa in itlaneltoquilitzin Dios, ihuan in itlayecoltilocatzin zenquizcatzopelic zenquizcahuiac = Wherefore God's faith and service to Him is perfectly sweet and fragrant
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 61.

teuahuiyayaliztli = sacred fragrance (late sixteenth 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), 15.

O cenquizcaahuiacatzopellicaychpochtzintle ma = Oh perfectly fragrant and sweet maiden (mid sixteenth 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), 121.

Attestations from sources in Spanish: 

ipampa in itlaneltoquilitzin Dios, ihuan in itlayecoltilocatzin zenquizcatzopelic zenquizcahuiac = pues que siendo tan dulce, tan suaue, y sabrosa la ley de Dios
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 60–61.

themes: 
Emotions
Sensory Perception (sound, smell, etc.)