coun‧ter‧vail‧ing /ˌkaʊntəˈveɪlɪŋ◂ $ -ər-/
adjective formal[
Date: 1300-1400;
Language: Old French;
Origin: contrevaloir, from contre- ( ⇒ counter-) + valoir 'to be worth']
with an equally strong but opposite effect
[TahlilGaran] Dictionary of Contemporary English ▲