counteragent From WikiWord, the free dictionary English Contents DefinitionsRelated wordsReferences DefinitionsnounAn agent having the opposite effect; an antidote. Related wordsSynonymsantiantidoteantidotecounteractantcounteractercounterpoisonantiantitoxinantipoisonantipathogenantidotantidotaryinverse agonistanticytokinecontrastimulantantagonistantihormoneantalkali References Wiktionary — counteragent Wikipedia — counteragent