Principal English Translation:
to jump off a cliff (apparently a suicidal or dangerous act), or to do this to others (see attestations)
Alonso de Molina:
tepexiuia. nino. (pret. oninotepexiui.) despeñarse.
tepexiuia. nite. (pret. onitetepexiui.) despeñar a otro.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 102v. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
TEPEHXIHUIĀ vrefl.vt to fling oneself headlong; to throw something, someone down from a height, or down a ravine / despeñarse (M), despeñar a otro (M) This is abundantly attested in T, where the internal glottal stop is missing. B has a single attestation with the glottal stop (f.1v). The high frequency in T is due to compounding with many possible locations, CUAUHTEPEHXIHUIĀ 'to hurl something down from a tree,' TLAPECHTEPEHXIHUIĀ 'to knock someone out of bed,' etc. See TEPEHXI-TL, -HUIĀ. TEPEHXIHUILIĀ applic. TEPEHXIHUIĀ. TEPEHXIHUĪHUA altern. nonact. TEPEHXIHUIĀ.TEPEHXIHUĪLŌ altern. nonact. TEPEHXIHUIĀ.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 229.
Lockhart’s Nahuatl as Written:
to hurl off a precipice, into an abyss, etc.; nic. Class 3: ōnictepehxihuih. tepehxitl precipice, -huia.
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), 234.
Attestations from sources in English:
Otimatoyaui, otimotepexiui. Quitoznequi: otimouitili, ayac omitzouitili. = You hurled yourself into the water, you flung yourself from a precipice. This means that you alone have gotten yourself into difficulties, no one else put your there.
Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 164–165.
Attestations from sources in Spanish:
yn omotepexihuique amanteca chaneqe Cuitlaxcohuapa ometin = se desbarrancaron dos oficiales, vecinos de Cuetlaxcohuapan (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 and México: Universidad Autónoma de Tlaxcala, Secretaría de Extensión Universitaria y Difusión Cultural, y Centro de Investigaciones y Estudios Superiores en Antropología Social, 1995), 400–401.