Origin and history of versus

"unfriendly opponent, enemy" (originally especially of Satan as the enemy of mankind), mid-14c., aduersere, from Anglo-French adverser (13c.), Old French adversarie (12c., Modern French adversaire) "hostile opponent, enemy," or directly from Latin adversarius "an opponent, rival, enemy," noun use of adjective meaning "opposite, hostile, contrary," literally "turned toward one," from adversus "turned against, turned toward, fronting, facing," figuratively "hostile, adverse, unfavorable," past participle of advertere "to turn toward," from ad "to" (see ad-) + vertere "to turn, turn back, be turned; convert, transform, translate; be changed" (see versus). The Latin word is glossed in Old English by wiðerbroca.

mid-15c., averten "to turn (something) aside" (the mind, the attention, etc.), from Old French avertir (later advertir) "to turn, direct; turn aside; make aware, inform" (12c.), from Latin advertere "turn toward, turn to," from ad "toward" (see ad-) + vertere "to turn" (see versus). The -d- was restored in English 16c. Especially in speaking or writing, "turn to (a topic) abruptly and plainly" (18c.). Related: Adverted; adverting.