adverse (adj.) Look up adverse at Dictionary.com
late 14c., "contrary, opposing," from Old French advers, earlier avers (13c., Modern French adverse) "antagonistic, unfriendly, contrary, foreign" (as in gent avers "infidel race"), from Latin 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). For distinction of use, see averse. Related: Adversely.