Huitzilopochtli.

Headword: 
Huitzilopochtli.
Principal English Translation: 

the name of a very important deity, associated with war, the sun, and the rain; the translation of the name is debated, e.g., "Left-Hand Side of the Hummingbird," "Hummingbird's Left," or, "Left of the Hummingbird" (and left was associated with the cardinal direction south)
See, for example, Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 93.

Orthographic Variants: 
Huitzinlilopochtl, Vitzilopuchtlj, Vitzilobuchtli, vitzilopuchtli, huītzilōpōchtli
Frances Karttunen: 

HUĪTZILŌPŌCH-TLI personal name Huitzilopochtli [(1)Bf.10r]. There is much disagreement on the meaning of this name. Contrary to some hypotheses, the first element, HUĪTZIL ‘hummingbird,’ modifies the second, ŌPŌCH-TLI ‘left-hand side.’ See HUĪTZIL-IN, ŌPŌCH-TLI.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 91.

"There seems to be a morpheme in ichpo:ch- 'young woman' and telpo:ch- 'young man' that may also occur in the deity names o:po:ch- and hui:zilo:po:ch-. It forms its plural by reduplication: po:po:ch-; cf. telpo:po:chtin 'young men' rather than simply tel.po:chtin."
Frances Karttunen, unpublished manuscript, used here with her permission.

Attestations from sources in English: 

Auh yntlapial catca quitlatlauhtiaya quiteomatia yn aquin quitocayotiaya tetzahuitl huitzilopochtli. ca tlahtohuaya. quinnotzaya. Yhuan oyntlan ne oquinmocniuhtiaya. in yehuatin azteca. (CC, f. 20r) = [And in their keeping was he to whom they supplicated, whom they considered a god, he whom they named the portent Huitzilopochtli. He spoke; he conversed with the Azteca; he lived among them and was their friend. (Chimalpahin 1997, 1:67)
Ezequiel G. Stear, Nahua Horizons: Writing, Persuasion, and Futurities in Colonial Mexico (Tucson: University of Arizona Press, 2025), 162.

auh in omjc, njman ie ic quixitinja, in inacaio in tzoalli, yn jiollo itech povia in Motecuçoma = And when he [Huitzilopochtli] had died, thereupon they broke up his body of amaranth seed dough. His heart was apportioned to Moctezuma (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 3 -- The Origin of the Gods, Part IV, 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, 1978), 6.

auh in imuztlaioc in miquia in Vitzilobuchtli in jnacaio. auh in quimjctiaia iehoatl in Quetzalcoatl: auh injc qujmjctiaia ie mitl, iacatecpaio conaqujliaia yiollopa = And upon the next day the body of Uitzilopochtli died. And he who slew him [was] the [priest known as] Quetzalcoatl. And [that] with which he slew him was a dart, pointed with flint, which he shot into his heart (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 3 -- The Origin of the Gods, Part IV, 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, 1978), 5.

Auh in Vitzilobuchtli: in iquac tlacatia in jnacaio in qujtlacatiliaia injlhujuh ipan. in iquac panquetzaliztli, in quichioaia tzoalli, michioauhtzoalli, ie in chicalotl = And when the body of Uitzilopochtli was shapen, when they gave it form upon their feast day of Panquetzaliztli, they made it of a dough of amaranth, of fish amaranth seed, which is a spiny herb (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 3 -- The Origin of the Gods, Part IV, 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, 1978), 5.

auh in Vitzilobuchtli: no mjtoaia tetzavitl, ichica ca ҫan jvitl, in temoc injc otztic in jnan in coacue: caiac nez in ita = And Uitzilopochtli was also known as an omen of evil; because from only a feather which fell, his mother Coatl icue conceived. For no one came forth as his father (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 3 -- The Origin of the Gods, Part IV, 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, 1978), 5.

In izquintin in inteteohuan, in amottàhuan, in amocolhuan, in quimoteotiaya, in Huitzilopochtli, copil, quetzalpatzactli, toçancol, quetzalcohuatl, tepuztecatl, yhuan huel oc miequintin tetica quiximaya quimoteotiaya, cequintin ça çan tlacame, ye o moch mímioque, Mictlan tlayhiyohuia, auh "cuac oc nemia tlalticpac, mococoaya, ciahuia, chocaya, mamanaya . . . àmo huel monòmapalehuiaya, quenin quinpalehuizque, in intech mopalehuilania? canel moch ahuilli, camanalli, çaçanilli, àtle ipan pouhqui" (León, Camino, fol. 12r). = All the gods your fathers and grandfathers used to worship- Huitzilopochtli, Copil, Quetzalpatzactli, Toçancol, Quetzalcohuatl, Tepuztecatl, and still very many others were fashioned out of stone and adored- some were just people, all have died already and are suffering in hell. But when they were still living on earth they used to get ill and tired, they used to weep and become disturbed. . . . They could not help themselves [so] how could they aid those who sought help from them? Since it is all an idle joke and fable it comes to nothing. [Abbreviations have been resolved.]
See Sell's comments in Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 25.

ioan naoatilo in jxqujchtin pipilti, injc cenqujçaqujuj in jitoalco vitzilopuchtli = and all the noblemen were commanded then to come to assemble in the courtyard of the Temple of Uitzilopochtli (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 8 -- Kings and Lords, no. 14, Part IX, 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, 1951), 61.

Auh in jquac in oqujz ilhujuh vitzilobuchtli, in iehoatl don po aluarado, ioan in espanoles in jtlan catca, mjiequjntin, qujnmjctique in mexica, in qujlhujqujxtiliaia vitzilobuchtli, ic vmpeuh in iauiotl. = And when came the feast day of Uitzilopochtli, Don Pedro Alvarado and the Spaniards who were with him slew many Mexicans while they were observing the feast day of Uitzilopochtli. Thus war began. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 8 -- Kings and Lords, no. 14, Part IX, 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, 1951), 22.

auh yn cana huecahuaya hualmoteteocaltihtiaque, quihualquehquetztiaque yn iTeocal ynTeouh huitzilopochtli = And in some places they stayed and built themselves a temple; they erected a temple for their god Huitzilopochtli. (central Mexico, early seventeenth century)
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. 1, 184–185.

When a tlatoani was invested in office, he was dressed in a green cape that had the same design of bones as that of the figure of Huitzilopochtli in the festival of Toxcatl. This was a festival in honor of Tezcatlipoca. Huitzilopochtli was identified with Tezcatlipoca. (central Mexico, sixteenth century)
Thelma Sullivan, "Tlatoani and tlatocayotl in the Sahagún manuscripts," Estudios de Cultura Nahuatl 14 (1980), 225–238. See esp. p. 229.

Vitzilubuchtli: çan maceoalli, çan tlacatl catca: naoalli, tetzaujtl, atlacacemelle, teixcuepanj: qujiocoianj in iaoiutl, iaotecanj, iaotlatoanj = Humming-bird from the Left (Uitzilopochtli), [was] only a common man, just a man. [He was] a sorcerer, an omen of evil; a madman, a deceiver, a creator of war, a war-lord, an instigator of war. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 1 -- The Gods; No. 14, Part 2, 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, 1950), 1.

Huitzilopochtli = Hummingbird Wizard
John A. Crow, The Epic of Latin America, 4th ed. (1992), 50.

Attestations from sources in Spanish: 

auh yn tlapial catca quitlatlauhtiaya quiteomatia yn aquin quitocayotiaya. tetzahuitl huitzilopochtli, catlatohuaya. quinnotzaya. tetzahuitl huitzilopochtli. catlahtohuaya. quinnotzaya. yhuan oyntlanne oquin mocniuhtiaya. in yehuantin Azteca. ynic yehica ynixpolihuia. yniz quitzonxiquipilli in teyollia yn teanimazhuan yn quinhuicaya ompa mictlan = Era su herencia el rogar y rezar a quien se denominaba Tetzahuitl Huitzilopochtli, pues que él les hablaba, les aconsejaba, vivía entre ellos, y se hacía amigo de los aztecas; por ello se perdían tantísimas almas que se llevaba al infierno. [Y era su depósito el rogar y rezar a quien se apellidaba Tetzahuitl Huitzilopochtli, pues les hablaba, les aconsejaba. y vivía entre ellos, se hacía amigo de ellos los aztecas; por esto era por lo que se perdían tantísimos espíritus humanos almas que llevaba al infierno.] (centro de México, s. XVII)
Fernando Alvarado Tezozomoc, Crónica mexicayotl; traducción directa del náhuatl por Adrián León (México: Universidad Nacional Autónoma de México, 1998), 12.

Yn ipa yecauh Mexico diablo ycal Huitzinilopochtl = En él se terminó en México la casa del diablo Huitzilopochtli. (Tlaxcala, 1662–1692)
Juan Buenaventura Zapata y Mendoza, Historia cronológica de la Noble Ciudad de Tlaxcala, transcripción paleográfica, traducción, presentación y notas por Luis Reyes García y Andrea Martínez Baracs (Tlaxcala and México: Universidad Autónoma de Tlaxcala, Secretaría de Extensión Universitaria y Difusión Cultural, y Centro de Investigaciones y Estudios Superiores en Antropología Social, 1995), 118–119.