cemicac.

Headword: 
cemicac.
Principal English Translation: 

always, for always, all the time, eternally, forever

Orthographic Variants: 
cemicac, zemicac, cemihcac
IPAspelling: 
semihkɑk
Alonso de Molina: 

cemicac. para siempre jamas. aduerbio.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 16r. col. 1. Thanks to Joe Campbell for providing the transcription.

Andrés de Olmos: 

siempre
Andrés de Olmos, Arte para aprender la lengua Mexicana, ed. Rémi Siméon, facsimile edition ed. Miguel León-Portilla (Guadalajara: Edmundo Aviña Levy, 1972), 189.

Lockhart’s Nahuatl as Written: 

cemihcac, particle. eternally. cē, ihcac.
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), 213.

Attestations from sources in English: 

ma dios espirito santo motlantzinco yes cemicac = May God the Holy Spirit always be with you (Guadalajara, 1653)
Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), Doc. 28, 176–177.

Neologisms:
cemihcac ichpuchtli = eternal Virgin
cemihcac nemiliztli = eternal life
cemihcac yoliliztli = eternal life
Susanne Klaus, Uprooted Christianity: The Preaching of the Christian Doctrine in Mexico, Based on Franciscan Sermons of the 16th Century Written in Nahuatl (Bonn: Bonner Amerikanistische Studien e. V. c/o Seminar für Völkerkunde, Universität Bonn, 1999), 251.