Definition
To behave irrationally or become confused and unable to understand what is happening.
精神失常；失去理智
Since losing his job, he's started acting a bit strange; I think he's losing the plot.
自從失業後，他開始有點奇怪的行為；我覺得他有點失去理智了。
She decided to invest all her money in that ridiculous project; she must be losing the plot.
她決定把所有的錢都投資在那個荒謬的項目上；她一定是失去理智了。
He doesn't know any of the details of the case; he seems to have completely lost the plot.
他對案件的細節一無所知；他似乎完全失去理智了。