Coanentzin.

Coanentzin, of Tlailotlacan Teohuacan
Susan Schroeder, Chimalpahin and the Kingdoms of Chalco, 1991, index.

Coanentzin = "die Als-SchlangeLebende" (which means, in English, "the one living as a serpent." The translation to German is based on the interpretation of the -nen- as coming from nemi, to live. (SW)
Eduard Stucken, Die weissen Götter, 1918.

"CŌĀNENTZIN, 1. A Chalcan princess d . 1477 (CHIM). 2. Fict. name, Snake Tongue. 76:21. Cf. COANENEPILLI." His entry for coanenepilli refers to a medicinal "passiflora" that "heals [male] genitals, cures nocturnal emissions (FC 11:148), relieves blocked seminal vesicles resulting from erotic dreams" (citing Hernández 2:229–30). [To truncate coanenepilli and have coanen as a result seems extreme.)
John Bierhorst, A Nahuatl-English Dictionary and Concordance to the Cantares Mexicanos, 1985, 88.

Another interpretation could be coa(tl) + nen(etl), producing Coanen, "Useless Serpent." This comes from hieroglyphic writing, where nenetl (deity image, doll, etc.) provides the phonetic element for nen, in vain, useless, idle.