There are several synonyms for the phrase "cheering up," including "brighten up," "lift spirits," "perk up," "boost morale," and "bring a smile to one's face." These phrases all convey the idea of providing happiness, hope, or positivity to someone who may be feeling down or discouraged. Other synonyms for cheering up could include "encouraging," "motivating," or "inspiring." It is important to recognize when someone may need a boost in their emotions and try to provide them with support and positivity in whatever way works best for them.