adverse (adj.) Look up adverse at Dictionary.com
late 14c., "contrary, opposing," from Old French 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, from ad- "to" (see ad-) + vertere "to turn" (see versus). Related: Adversely.