be missing some of (one's) marbles

be missing some of (one's) marbles

To be mentally deficient, incompetent, or deranged; to be of unsound mind. My poor grandmother is missing some of her marbles after her stroke. I've been so sleep deprived lately that it feels like I'm missing some of my marbles!

See also: marble, missing, of

Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.