cold feet
失去勇气或信心，在重要时刻退缩
口语·表示临阵退缩或紧张
英文释义
to suddenly become hesitant or fearful about something one was previously enthusiastic or confident about
例句
I was all set to propose, but then I got cold feet and couldn't go through with it.
典故来源
源自军事术语，指士兵在严寒中因脚冻伤而无法前进，后引申为临阵退缩。