have a screw loose
思维或行为上有问题，不正常或疯狂
口语·形容古怪
英文释义
to be mentally unstable or eccentric
例句
He talks to his plants every day; some people say he has a screw loose.
典故来源
源自机械比喻，螺丝松动导致机器失常，形容行为古怪。