Meaning of “cheer (sb) up” - Learner’s Dictionary

cheer (sb) up

phrasal verb with cheer us uk /tʃɪər/ verb

B2 to stop feeling sad, or to make someone feel happier:

Cheer up. It's not the end of the world.
Let's send her some chocolates to cheer her up.

(Definition of “cheer (sb) up” from the Cambridge Learner’s Dictionary © Cambridge University Press)