Principal English Translation:
towards, or against (adverb) (see Molina); in the direction of (see attestations)
Alonso de Molina:
iuicpa. hazia, o contra. aduerbio.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 44r. col. 1. Thanks to Joe Campbell for providing the transcription.
Attestations from sources in English:
"ihuicpa yn chiyauhtla" = In the direction of Chiyauhtla, i.e. to the north (from Tetzcoco); "ihuicpa Norte" = to the North. And "yhuicpa sur yn chalcopahuic" = toward south, toward Chalco. (Tetzcoco 1596)
Juan López y Magaña, "Aspects of the Nahuatl Heritage of Juan Baustista de Pomar," M.A. Thesis, UCLA, 1980; see Document 4 in the appendices, 81–85.
inihuicpa = against (s. XVIII; by Dr. Bartolache, who was not a native speaker but had studied classical Nahuatl)
Neville Stiles, Jeff Burnham, James Nauman, "Los concejos médicos del Dr. Bartolache sobre las pastillas de fierro: Un documento colonial en el náhuatl del siglo XVIII," Estudios de Cultural Náhuatl 19 (1989), 269–287, ver página 279.
Attestations from sources in Spanish:
inihuicpa = contra (s. XVIII; por un Dr. Bartolache, quien no era nativohablante, pero estudiante del náhuatl clásico)
Neville Stiles, Jeff Burnham, James Nauman, "Los concejos médicos del Dr. Bartolache sobre las pastillas de fierro: Un documento colonial en el náhuatl del siglo XVIII," Estudios de Cultural Náhuatl 19 (1989), 269–287, ver página 279.