"Power-up" refers to an action of boosting or increasing power and strength, usually related to games or sports. Synonyms for "power-up" include "strengthen," "empower," "energize," "rejuvenate," "revitalize," "fortify," and "enliven." "Strengthen" refers to the improvement of physical or mental ability to perform a task, while "empower" implies giving someone the authority to do something. "Energize" and "revitalize" signify restoring or replenishing energy and enthusiasm. "Fortify" suggests reinforcing and supporting something to make it stronger, and "enliven" describes making something more interesting or exciting. All these synonyms can be used in various contexts and convey the idea of enhancing or boosting power and performance.