Principal English Translation: 

a priestly name (and refers to the regalia worn by the priest that seems to have included perhaps stinky black feathers); a botanical name (for a rare bean?); a personal name--used by some Nahua men of the ruling class in the autonomous era and after colonization, but also a name used by more humble tribute payers (see attestations)

Orthographic Variants: 
Tlilpopoqui, Tlilpotoncatzin
Attestations from sources in English: 

ytoca tlilpopoqui = named Tlilpotonqui (we are reproducing here the spelling as it appears in the publication) (Cuernavaca region, ca. 1540s)
The Book of Tributes: Early Sixteenth-Century Nahuatl Censuses from Morelos, ed. and transl. S. L. Cline, (Los Angeles: UCLA Latin American Center Publications, 1993), 146–147. For another example, see 158–159, and one on 162–163.

The Gran Diccionario Nahuatl cites Wimmer: "parure, qui est couvert de colle et de plumes noires / botanique, nom d'une plante. / nom ésotérique du haricot. / nom sacerdotal. / n.pers." An ensemble of finery with black feathers glued onto it. Also, a plant, a botanical name. An esoteric type of bean. A priest's name. A personal name.

There was an illustrious man named Tlilpotonqui or Tlilpotoncatzin who was the son of Tlacaeleltzin. This Tlilpotonqui had the title cihuacoatl, as did his father, Tlacaeleltzin cihuacoatl. Tlilpotonqui claimed Huitzilihuitl as his grandfather (father of Tlacaeleltzin, who was the son of the lord Acamapichtli, first ruler of Tenochtitlan). There was also a don Miguel Tlilpotonqui Carsetero, a child born outside of wedlock to a doña María, daughter of don Diego Tehuetzquititzin. As can be seen in the "see also" field here, Chimalpahin used unfortunate loanwords taken from Spanish to describe his birth status.
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 2, 88–89, 104–105.