An opposing force.

operations. those space or trans-atmospheric activities aimed at opposing or defending against threatening force anywhere on the planet or in the region of space. Although counterforce activities are defensive in intent, they do not preclude defense by offensive action. Counterforce activities include the use of information and weather as weapons. They also include defense against non-human threats to the vitality and security of the United States and the people on the planet.

Military strategies, attacks, or weapons directed against an opponent's military forces, command posts, and war-fighting targets.