Which term describes the approach that emphasizes avoiding detection in military operations?

The term that best describes the approach emphasizing avoiding detection in military operations is "stealthy." This concept is integral to military strategies where the element of surprise and concealment are paramount. Stealthy operations utilize various techniques and technologies to minimize visibility and sound, such as low-observable aircraft, silent movement, and other methods designed to keep forces and activities hidden from enemy observation.

In contrast, the other terms convey different tactical approaches. For instance, a forceful approach typically involves direct engagement and aggression, while a deliberate strategy focuses on careful planning and execution rather than stealth. Rapid suggests speed and quick maneuvering but does not inherently contain the emphasis on avoiding detection. Thus, "stealthy" accurately encapsulates the strategy of conducting military operations with an aim to remain undetected, making it the correct choice in this context.