What type of attack involves a surprise from concealed positions to degrade enemy effectiveness?

An ambush is a tactical maneuver that involves attacking an enemy unexpectedly from concealed positions, typically with the goal of catching them off guard and inflicting maximum damage. This type of attack is designed to degrade the enemy's effectiveness by striking when they are least prepared, often resulting in confusion and disruption within their ranks.

In the context of combat, effective ambushes rely on careful planning and positioning to ensure that those conducting the ambush have a significant advantage over their unsuspecting targets. The element of surprise is critical, as it allows the ambushing force to exploit the enemy's vulnerabilities and achieve tactical objectives quickly and efficiently.

Other types of attacks, such as a counterattack, involve responding to an enemy assault after it has begun, and a feint is meant to deceive the enemy about the direction or timing of an attack. Ethos, in this context, does not pertain to military strategies or types of attacks. Therefore, the definition and execution of an ambush make it the correct choice for this question, emphasizing its role as a surprise tactic to diminish enemy effectiveness.