When we talk about the opposite of the term "power down," we refer to activities or processes that involve increasing energy or activity levels. Some antonyms for power down could include words like energize, activate, charge up, stimulate, rev up, and ignite. These words describe actions that increase the intensity, activity, or productivity of an individual or system. For example, when we energize our body with a workout or a nourishing meal, it is the opposite of shutting down or powering off. Similarly, when we stimulate our mind with new ideas, activities, or challenges, we become more productive and active, rather than slowing down or becoming inactive.