What term describes using less power than necessary to achieve a faster rate of airspeed change?

The term that best describes using less power than necessary to achieve a faster rate of airspeed change is "Underpower." In aviation, underpower refers to the strategic use of less engine power to create a situation where the aircraft can still accelerate or decelerate efficiently. This is often used in scenarios such as descents or during specific phases of flight, where managing excess power effectively can help maintain or enhance performance without unnecessary fuel consumption or drag.

In contrast, overthrust usually implies providing excess power, which may not be efficient for the desired rate of airspeed change. Throttle management encompasses a broader range of techniques for adjusting power, which might not specifically relate to the concept of using less power effectively. Lastly, power reduction simply indicates lowering power settings, but it does not specifically convey the idea of optimizing airspeed change with less power.