How is “buck up” used?

In Sons of the Desert (1933), one line is: “Now, buck up. Go in and tell her that you're going to the convention.”

Which movie is “buck up” from?

The clip at the top of this page is from Sons of the Desert (1933).

Now, buck up. Go in and tell her that you're going to the convention.

8 作品で登場 · 1 本目

to become more cheerful

古風 · 9 本の映画に登場

オックスフォード映画の 60%
to become more cheerful
Well, Edward, you'll just need to buck up.
Come on. Buck up.

定義：Oxford Advanced Learner's Dictionary 第 9 版