tlacuilo.

Headword: 
tlacuilo.
Principal English Translation: 

notary, scribe, painter (see Molina); one who writes or paints (see Karttunen)

Orthographic Variants: 
tlahcuilo, tlacuillo, amatlacuillo, tlahcuiloh, tlacuiloqui
IPAspelling: 
tɬɑhkwiloh
Alonso de Molina: 

tlacuilo. escriuano, o pintor.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 120r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

TLAHCUILOH one who writes or paints / escribano o pintor (M) [(3)Cf.7r,52r,(1)Rp.43]. Z has a variant TLAHCUILOHQUI with the same sense, while M has tlacuiloani. See TLAHCUILOĀ.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 261.

Attestations from sources in English: 

in tlacuilo, tlilli, tlapalli, tlilatl, ialuil, toltecatl tlachichiuhqui, tlatecullaliani, tlateculaniani, tlalilani, tlilpatlac, tlapaltecini tlapallaliani. = The scribe: writings, ink [are] his special skills. [He is] a craftsman, an artist, a user of charcoal, a drawer with charcoal; a painter who dissolves colors, grinds pigments, uses colors. (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), 28.

quintemozq Omentin tipotantosme no omentin mayordomosme auh no çe onyez amatlacuillo = they will search for two diputados; also two mayordormos. Here will also be a notary.
Fray Alonso de Molina, Nahua Confraternities in Early Colonial Mexico: The 1552 Nahuatl Ordinances of fray Alonso de Molina, OFM, ed. and trans., Barry D. Sell (Berkeley: Academy of American Franciscan History, 2002), 100–101.

tlacuilo = scribe or painter
Susan Kellogg, Law and the Transformation of Aztec Culture, 1500–1700 (Norman and London: University of Oklahoma Press, 1995), 227.

Tlàcuilòque can mean either they are scribes or they wrote. In other words the plural noun can be confused with the plural third person preterite of the verb.
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 160.

[tla]cuiloqui = scribe (Tepetlaoztoc, sixteenth century)
Barbara J. Williams and H. R. Harvey, The Códice de Santa María Asunción: Facsimile and Commentary: Households and Lands in Sixteenth-Century Tepetlaoztoc (Salt Lake City: University of Utah Press, 1997), 71.

Attestations from sources in Spanish: 

Yn tlacuiloque escrivanome hevatl yntequiuh yn quichivazque yn quicuilozque (f. 6 r.) tenavatili mandamiento inic ylpilozque yn otlatlacoque yvan quichivazque quicuilozque yn itemoloca ynimelavaca neltiliztlatolli in informacion ymotquiz mexiquo ilpitiyazque tlatlacovani = Es obligación de los escribanos que hagan, que escriban la orden, el mandamiento para que sean tomados presos los que han cometido delitos. Y harán, escribirán la investigación, la correcta información que se llevará a México, con los delincuentes presos (Cuauhtinchan, Puebla, s. XVI)
Luis Reyes García, "Ordenanzas para el gobierno de Cuauhtinchan, año de 1559," Estudios de Cultura Náhuatl 10 (1972), 272–273.

quinpohuaya in domingotica quimittaz in cacapitanme tlacuilloca[n] capitan ytoca Joan Ycnotzin = los contaba los días domingo para ver a los diferentes capitanes. El capitán de los pintores [tlacuillocan] se llama Juan Ycnotzin (ca. 1582, Mexico City)
Luis Reyes García, ¿Como te confundes? ¿Acaso no somos conquistados? Anales de Juan Bautista (Mexico: Centro de Investigaciones y Estudios Superiores en Antropología Social, Biblioteca Lorenzo Boturini Insigne y Nacional Basílica de Guadalupe, 2001), 180–181.

Nehuatl nitlacuilo ypan inin Comonidad = soy, el escribiente aquí en esta Comunidad (Estado de Hidalgo, ca. 1722?)
Rocío Cortés, El "nahuatlato Alvarado" y el Tlalamatl Huauhquilpan: Mecanismos de la memoria colectiva de una comunidad indígena (New York: Hispanic Seminary of Medieval Studies, Colonial Spanish American Series, 2011), 35, 47.

X[Christo]val de Sant Matheo Quauhtli, ytlacuilocauh mochiuh = Cristóbal de San Mateo Quauhtli fue su escribano (ca. 1582, México)
Luis Reyes García, ¿Como te confundes? ¿Acaso no somos conquistados? Anales de Juan Bautista (México: Centro de Investigaciones y Estudios Superiores en Antropología Social, Biblioteca Lorenzo Boturini Insigne y Nacional Basílica de Guadalupe, 2001), 172–173.