contra (prep., adv.)
"against, over against, opposite, on the opposite side; on the contrary, contrariwise," mid-14c., from Latin contra (prep. and adv.) "against," originally "in comparison with," ablative singular feminine of *com-teros, from Old Latin com "with, together" (see com-) + -tr, zero-degree form of the comparative suffix -ter-.
"anti-Sandinista Nicaraguan," 1981, short for Spanish contrarrevolucionario "counter-revolutionary" (n.); see contra-. Contra was earlier used as a noun in English, directly from Latin, in the senses of "a thing which is against another" (1778); "the contrary or opposite" (1640s). Related: Contras.