Light up is a commonly used phrase that refers to illuminating or brightening an object, place, or situation. There are many synonyms for light up that can be used to express the same or similar meanings. Some of these include brighten, illuminate, shine, glow, radiate, lighten, enhance, intensify, enliven, and kindle. Each of these synonyms can be used in different contexts, such as a person's smile that lights up a room or the sun that illuminates the surrounding landscape. Ultimately, using synonyms for light up allows for more variety and creativity in language, while still conveying the intended meaning.