Principal English Translation:
to become pregnant (reflexive) or to impregnate someone (transitive)
Alonso de Molina:
otztia. n. (pret. onotztic.) empreñarse.
otztia. nite. (pret. oniteotzti.) empreñar a otra.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 78r. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
ŌTZTIĀ vrefl, vt to become pregnant; to impregnate someone / embarazarse, concebir (la mujer) (X), engendrar (el hombre) (X) M and X have an intransitive verb 'to become pregnant' in addition to a transitive verb 'to cause someone to become pregnant,’ while T has this as a reflexive verb 'to conceive.' M and X give the preterir as onotztic, but T has it as a regular -IĀ verb. X has Z for TZ. See ŌTZ-TLI. ŌTZTĪLŌ nonact. ŌTZTIĀ.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 180.
Attestations from sources in English:
yc nimā yhquac opeuh yn ootzitic = Thus at the time she began to be pregnant. (central Mexico, early seventeenth century)
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 1, 122–123.
moaniulcatzi, ie uel ilamatzi in outztic, ca ie tlatquitica = your relative, who is already quite an old woman is pregnant (late sixteenth century, Central Mexico)
Louise M. Burkhart, Before Guadalupe: The Virgin Mary in Early Colonial Nahuatl Literature, Institute for Mesoamerican Studies Monograph 13 (Albany: University at Albany, 2001), 42.
Attestations from sources in Spanish:
Yvan yz ҫiva otztiticate amo tepoztli quintlalilizque amo ylpilozque amo mecavitecozque amo no tlaltzacuiltilozque ynic amo motlatlaxilizque ynic amo tle ypan mochivaz piltzintli teytec cah yvan yn tenantzin = Y a las mujeres embarazadas no les pondrán hierros, no serán atadas, no serán azotadas, tampoco serán castigadas, para que no se vayan a herir, para que no les vaya a pasar algo a la madre y al niño que está en sus entrañas (Cuauhtinchan, Puebla, s. XVI)
Luis Reyes García, "Ordenanzas para el gobierno de Cuauhtinchan, año de 1559," Estudios de Cultura Náhuatl 10 (1972), 272–273.