The phrasal verb "brighten up" is predominantly used in informal contexts, though it can appear in formal settings when describing a change in mood or atmosphere. This expression generally conveys an improvement or enhancement, both literally and figuratively. Literally, it can refer to making a space more illuminated, often by increasing light or introducing lively decorations. Figuratively, it often describes a person becoming more cheerful or a situation becoming more positive, as in "She really brightened up the party with her stories." In informal settings, it might also be used to encourage someone to adopt a more positive attitude. Its versatility in conveying both physical and emotional change makes it a useful phrase in everyday conversation.
B1
PreIntermediate
1. To make a place or situation more cheerful or lively.
The new paint color really brightens up the kitchen.
Let's put some music on to brighten up this dull evening.
2. To improve one's mood or outlook; to make someone happier.
Charlie seemed down this morning, but a phone call from his mom brightened him up.
A good breakfast can really brighten you up in the morning.