Which term refers to separating a force from its support to reduce its effectiveness?

The term that refers to separating a force from its support to reduce its effectiveness is "Isolate." When a force is isolated, it becomes vulnerable and less capable of carrying out its mission because it lacks the support that provides reinforcement, supplies, and situational awareness. This tactic is often employed in military operations to weaken the enemy's capabilities and to create opportunities for engagement and defeat.

By isolating a force, commanders aim to disrupt its command and control, logistical sustainment, and reinforcements. This can lead to a significant tactical advantage, as an isolated enemy is typically less coordinated and more accessible to attack. In contrast, guard, occupy, and follow and support refer to different operational maneuvers and roles that involve maintaining contact with forces or controlling territory, which do not emphasize the act of separation as their primary objective.