IPA: //ˌkaʊntəˈæktɪv//
KK: /ˈkaʊntərˌæktɪv/
Having the effect of opposing or neutralizing something.
The medication has a counteractive effect on the symptoms of the disease.
Counteractive → It is formed from "counter-" (meaning against) and "active" (from Latin "activus", meaning to do or to act). The word describes something that acts against or opposes another action.
Think of something that works 'against' ('counter-') an action or effect — that's why counteractive means opposing an action.