Principal English Translation: 

to trot, go along trotting (see Molina); to hang (see Lockhart); may also have something to do with being buried (see Sahagún, attestations)

Alonso de Molina: 

Aactiuh. n. yr trotando. Prete. onaactia.
Alonso de Molina, Vocabulario en lengua mexicana y castellana, 1571, (www.idiez.org.mx), f. 1r.

Attestations from sources in English: 

itech ieietiuh, itech aactiuh = to which were fixed, from which hung
James Lockhart, We People Here: Nahuatl Accounts of the Conquest of Mexico, Repertorium Columbianum v. 1 (Los Angeles: UCLA Center for Medieval and Renaissance Studies, 1993), 70.auh çan no iquac eoatlatilo, onmotlatia, onmocacaoa, yn jmeoaio tlaca, vmpa iopico onaactiuj = And also at that time were hidden away the human skins—placed aside, abandoned. There at the Temple of Yopitli they were all buried. (16th 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), 55.