lose your marbles
失去理智或心智不健全
口语·形容某人行为古怪或精神失常
英文释义
to lose one's mind or sanity; to become mentally unstable
例句
Grandpa started talking to his plants again; I think he's losing his marbles.
典故来源
源自20世纪初的俚语，'marbles'指代理智或头脑，失去弹珠比喻失去心智。