The Collaborative International Dictionary
Counterforce \Coun"ter*force`\ (-f?rs`), n. An opposing force.
Wiktionary
n. A force that opposes another force.
Wikipedia
In nuclear strategy, a counterforce target is one that has a military value, such as a launch silo for intercontinental ballistic missiles, an airbase at which nuclear-armed bombers are stationed, a homeport for ballistic missile submarines, or a command and control installation. The intent of a counterforce strategy (i.e., attacking counterforce targets with nuclear weapons) is to disarm an adversary by destroying its nuclear weapons before they can be launched, thereby minimizing the impact of a retaliatory second strike. However, counterforce attacks are also possible in a second strike, especially with weapons like UGM-133 Trident II. A counterforce target is distinguished from a countervalue target, which includes an adversary's population, knowledge, economic, or political resources. In other words, a counterforce strike is against an adversary's military while a countervalue strike is against an adversary's cities. A closely related tactic is the decapitation strike, which by destroying an enemy's nuclear command and control facilities similarly intends to eliminate or reduce their ability to launch a second strike.
Usage examples of "counterforce".
The shield sparkled when the crackles of light managed to reach it, dissipating the power with counterforces, grounding the magic with an opposite.
And in a sense they were a nonallied counterforce, separated from the Human as well as the Invid cause.