lose one's marbles

== English == === Pronunciation === === Verb === lose one's marbles (third-person singular simple present loses one's marbles, present participle losing one's marbles, simple past and past participle lost one's marbles) Synonym of lose one's mind (“to become crazy”). 1981 April 13, New York magazine, vol. 14, no. 15, There it was again, the suggestion that the governor had lost his marbles. And, to be truthful, Breslin is a bit late on the loony angle.