chichi.

Headword: 
chichi.
Principal English Translation: 

a male or a female dog

IPAspelling: 
tʃitʃi
Alonso de Molina: 

chichi. perro, o perra.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 19v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

CHICHI pl: -MEH dog / perro o perra (M) This is commonly used with the diminutive compounding element –TŌN. Since CHICHI is an absolutiveless noun, the compound is also absolutiveless, CHICHITŌN. CHICHI contrasts with CHĪCHĪ ‘to suckle’ and CHIHCHI ‘sáliva.’
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 47.

Attestations from sources in English: 

quinechicozque yn chichime = he ordered that the dogs be rounded up
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 134–135.

Teizolo, tecatzauh. Inin tlatolli: itechpa mitoa: in amo qualli nemiliztli, azo tlatoltica: mitoaya: intla aca pilli, anozo tecutli in zan iliuiz tlatoa, in iuhqui chichi. = Something that mars and soils people. This was said about a way of living or speaking that was wrong. It was said if some noble or lord spoke rashly or snapped at people savagely like a dog.
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 174–175.

This is an example of a suffixless noun (no -tl, -tli, or -in ending).
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 232.

amo iuhquj tichichi, ticquativetziz, ticquetzontivetziz in tlalticpacaiotl = thou art not to devour, to gulp down the carnal life as if thou wert a dog (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 116.

Attestations from sources in Spanish: 

Inimequez nahualtin tlanonotzalo quemen mocuepa quemanian de yolcatl, de chichi, de miztli, de cuanaca, o nozo mocuepa in texcaltin. = Cuentan que estos nahuales a veces se vuelven animales--perros, gatos, gallinas--o se vuelven peñascos. (s. XX, Milpa Alta)
Los cuentos en náhuatl de Doña Luz Jiménez, recop. Fernando Horcasitas y Sarah O. de Ford (México: UNAM, 1979), 32–33.

themes: 
Animals, Bugs, Insects, Reptiles, Fish, etc.