tecpilli.

Headword: 
tecpilli.
Principal English Translation: 

a person of the nobility, a lord (see Molina and Karttunen)

IPAspelling: 
teːkpilli
Alonso de Molina: 

tecpilli. hidalgo.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 93v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

TĒCPIL-LI nobleman / hidalgo, persona noble, caballero (C) [(2)Bf.5V,9v,(4)Cf.57v,80r]. See TĒUC-TLI, PIL-LI.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 217.

Attestations from sources in English: 

Jn tecpilli tlaçotli, uel tlaçotli, tlaçotli yn iiollo, muchi tlacatl itlaço, aiac itzcuin iuiiaio, iocuxcaio, tlatlaçotla, tlamauiçoa, tlamauiztilia, tepepetla, tetlatlatlauhtia. = The noble [is] esteemed, highly esteemed, noble of birth. All people [have] his esteem. [He is] no one's dog. [He is] tranquil, peaceful. He esteems, admires, shows reverence for things. He compliments others; he speaks graciously to them. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, 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), 16.

ytecpilcac = her lordly sandals
Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 98.

Attestations from sources in Spanish: 

ynic monotza tecpilpa = Así se conversaron entre los tecpiltin (Tetzcoco, 1580)
Benjamin Daniel Johnson, “Transcripción de los documentos Nahuas de Tezcoco en los Papeles de la Embajada Americana resguardados en el Archivo Histórico de la Biblioteca Nacional de Antropología e Historia de México”, en Documentos nahuas de Tezcoco, Vol. 1, ed. Javier Eduardo Ramírez López (Texcoco: Diócesis de Texcoco, 2018), 74–75.

themes: 
Social Hierarchy, Commoners, Elites