namictli.

Headword: 
namictli.
Principal English Translation: 

wife, husband, spouse

IPAspelling: 
nɑːmiktɬi
Alonso de Molina: 

namictli. casado o casada.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 062v. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

NĀMIC-TLI pl NĀNĀMICTIN spouse / casado o casada (M) See NĀMIQU(I).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 158.

Lockhart’s Nahuatl as Written: 

spouse male or female; something equal and complementary, matching. related to nāmiqui. 226
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 226.

Attestations from sources in English: 

The Virgin Mary could be the namictli (spouse) to Joseph and the nemactli (wife) to God. Namictli is related to namiqui, "to meet or find."
Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 50.

tiasque cabecera yca mochi tonamichuan ompa titequipanosque = we are to go there to the head town with all our wives and are to work there (Guadalajara, 1653)
Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), Doc. 28, 174–175.

Typically possessed:
nonamic, nonamictzin = my spouse
inamic (ynamic, etc.) = his/her spouse

-namic = spouse, husband, wife. Even though -namic meant spouse and was used for both genders in sixteenth-century Culhuacan, in the Toluca Valley in the eighteenth century it had come to mean simply husband and was paired with -cihuahuatzin (one's woman). The transition apparently came in the late seventeenth century. Namictli and cihuahuatli were thus becoming like the Spanish, marido and mujer.
Caterina Pizzigoni, ed., Testaments of Toluca (Stanford: Stanford University Press and UCLA Latin American Center Publications, 2007), 20–21.

aҫo qujn ie ic itlati in qujnequj tlalticpacaiotl, injc timaceoalti in monamjc = Perhaps presently there ariseth her desire; she longeth for the carnal relations which thou owest thy spouse (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 117.

in aiamo onmaci piltzintli, in qujn ce, in qujn vme, in qujn ei metztli, ҫa oc quenman moquazque in jnamjc = before the baby had attained form, after one, two, [or] three months, her husband should still at times be accepted (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, 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), 156.

Attestations from sources in Spanish: 

auh yn inamichuan mochi quihuicaque = Y a sus esposas, a todas las raptaron. (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 y México: Universidad Autónoma de Tlaxcala, Secretaría de Extensión Universitaria y Difusión Cultural, y Centro de Investigaciones y Estudios Superiores en Antropología Social, 1995), 184–185.

yn ipan nica yn tlali amo notlal ytlal yn nonami catca ytoca catca Juana ocan onechcauhteuac = la tierra en que estoy no es mía es tierra de mi mujer que era, que se llamaba Juana, que ahí me dejó
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 1, Testamentos en castellano del siglo XVI y en náhuatl y castellano de Ocotelulco de los siglos XVI y XVII, eds. Teresa Rojas Rabiela, Elsa Leticia Rea López, y Constantino Medina Lima (Mexico: CIESAS, 1999), 280–281.

ynonamictzin catca Pedro Tlapalpolo yciuatzin catca ycuen auh ononechmomaquiquiliteuac ycan testamento = mi marido [difunto] que era Pedro Tlapalpolo, tierra que era de su mujer [difunta], me la dejó dada en su testamento
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 1, Testamentos en castellano del siglo XVI y en náhuatl y castellano de Ocotelulco de los siglos XVI y XVII, eds. Teresa Rojas Rabiela, Elsa Leticia Rea López, y Constantino Medina Lima (Mexico: CIESAS, 1999), 226-227.

Cuix tinamique? cuix ticpia monamic. = Eres casado.
Antonio Vázquez Gastelu, Arte de lengua mexicana (Puebla de los Angeles, México: Imprenta Nueva de Diego Fernández de León, 1689), 33r.

ynonamictzin ytoca Maria Castilanxochitl = mi mujer María Caxtilanxochitl
Vidas y bienes olvidados: Testamentos indígenas novohispanos, vol. 1, Testamentos en castellano del siglo XVI y en náhuatl y castellano de Ocotelulco de los siglos XVI y XVII, eds. Teresa Rojas Rabiela, Elsa Leticia Rea López, y Constantino Medina Lima (Santa Bárbara, Tamasolco, Ocotelulco, Tlaxcala), 310–311.