za cemi.

Headword: 
za cemi.
Principal English Translation: 

finally, or just this once, or as a farewell (adverb)

Orthographic Variants: 
ça cemi
Alonso de Molina: 

za cemi. ultimadamente, o esta sola vez, o por despedida. aduerbio.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 13v. col. 2. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

once and for all; ultimately
Robert Haskett and Stephanie Wood's notes from Nahuatl sessions with James Lockhart and subsequent research.

See also: 
za cemmayan.