Wiktionary
n. An agent having the opposite effect; an antidote.
Usage examples of "counteragent".
It was as if he were incorporating the mass of the counteragent into his matrix more rapidly than he could convert the substrate of the ship.
The counteragents we've developed to the others are, unfortunately, less effective and require a stepped series of injections.
Every version of Harper's Touchdown is going to need new counteragents against the cyclic insect mutations, for instance.
I have begun researching some of the Dokaalan doctors’ older medical records in order to gain some insight into the drugs that were once prescribed for all of the colonists as counteragents to the radiation.
But Venora’s drugs were obviously still roiling within his blood, along with whatever counteragents Suran’s unknown confederates had used to get him back on his feet only a few dierhu after she had last checked in on him.
Truthfully, the physician wasn't even sure there was a counteragent effective against the lethal war gas.