When you want to express the idea of something or someone getting better, livelier or more enthusiastic, the phrase "perk up" is often used. But there are many other words and phrases that can be used to convey the same meaning. For instance, some synonyms for "perk up" are "brighten up," "revive," "booster," "cheer up," "become livelier," "be invigorated," and "be re-energized." Other alternatives include "pick up," "bounce back," "rejuvenate," "energize," "galvanize," and "enliven," among others. So, the next time you want to express that someone or something is getting better or livelier, consider using one of these synonyms for "perk up" to add variety to your vocabulary.