cheer up phrasal verb ( see also ↑ cheer )
1 . to become less sad, or to make someone feel less sad:
Cheer up! The worst is over.
They cheered up when they saw us coming along.
cheer somebody ↔ up
Here’s a bit of news that will cheer you up.
You both need cheering up, I think.
2 . cheer something ↔ up to make a place look more attractive:
I bought some posters to cheer the place up a bit.