Pull yourself together; do you want to show the white feather in front of these people?

振作起来！难道你甘愿在这些人面前示弱吗？

《新英汉大辞典》

Don't show the white feather to the enemy.

别向敌人展示白羽毛。

youdao

Eg: Don't show the white feather, fight for your beliefs.

这个说法来自斗鸡，如鸡的羽毛出现白色，显示饲养得不好。

youdao

John's friend, the Indian Seth White Feather offered John a way to make money during the winter when it was too cold for farming.

VOA: special.2010.06.26

Kaschei's efforts to keep his female captives in submission and put Ivan under his spell turn futile once the white-clad hero waves the feather he gained for granting freedom to the firebird.

WSJ: Firebird | American Ballet Theatre | Ratmansky's Fresh Fantasy | By Robert Greskovic

The reflection of my white cotton underwear neared opacity, realness, and the gold chain with the gold feather glimmered.

NEWYORKER: Reverting to a Wild State