Principal English Translation: 

mesquite tree; its sap was used for ink (see Karttunen and Molina); also, a person's name (attested male)

Orthographic Variants: 
Alonso de Molina: 

mizquitl. arbol de goma para tinta.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 57v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

MIZQUI-TL mesquite / árbol de goma para tinta (M), mesquite [(1)Bf. 4r, (2)Tp. 142, (5)Xp. 54,86]. X marks the vowel of this long, while T reduplicates it to yield MĪMIZQUI-TL.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 149.

Attestations from sources in English: 

ytoca mizquitl = named Mizquitl (male) (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), 132–133.

mizquitl = mesquites; may also refer to the warrior king specifically (late sixteenth century, Tetzcoco?)
Ballads of the Lords of New Spain: The Codex Romances de los Señores de la Nueva España, transcribed and translated by John Bierhorst (Austin: University of Texas Press, 2009), 32.

ynjn coatlapechtli, quaujtl in tlaxixintli, iuhqujn cocoa, naujntin in motzinnamjctoque: nauhcampa caca yn jntzontecon: … mjchioauhtzoalli, ynjc qujpepechoaia, yn jmizqujo, ca mizqujquaujtl, in tlaxintli, yn ixiptla muchipa catca, yn oqujpepechoque = This serpent bench was hewn of wood, to represent serpents; four sides carried the tails; four sides carried their heads… They covered [Uitzilopochtli’s] mesquite wood framework with fish amaranth dough; for his figure was always hewn of mesquite wood, which they covered. (sixteenth century, Mexico City)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2—The Ceremonies, No. 14, Part III, 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), 69.