lose one's marbles

idiomPart ofmarble

lose one's marbles — idiom

1. to become crazy or mentally confused, especially as a result of old age

1.慣用語
釋義

to become crazy or mentally confused, especially as a result of old age

例句

Grandfather keeps talking to the television — I think he is losing his marbles.

Anyone who tries to climb that wall in the rain must have lost their marbles.