IPA: /ˈkaʊntərˌɛfərt/
KK: /ˈkaʊntərˌɛfərt/
An action taken to oppose or counteract another action.
The team made a countereffort to regain control of the game after falling behind.
Countereffort → It is formed from "counter-" (meaning against) and "effort" (from Old French *esforcier*, meaning to exert oneself). The word describes an effort made in opposition to another effort.
Think of making an 'effort' to do something 'against' another action — that's why countereffort means an effort made to oppose.