bats in the belfry

phrase

variants or chiefly US bats in one's belfry

informal + old-fashioned

—used to say that someone is mentally unsound or very eccentric

They might be strange and deranged, but The Addams Family isn't the only domestic unit with bats in the belfry.

—Brian Kelly

They might say he's not quite all there. Or, he is a few bricks short of a load. They used to say he's got bats in his belfry. Or, he's not playing with a full deck.

—Mary B. Olsen

Word History

First Known Use

1897, in the meaning defined above