have got bats in (one's) belfry

have got bats in (one's) belfry

To be crazy; to act, think, or behave in a foolish or nonsensical manner. Tommy has got bats in his belfry if he thinks he can convince our mother to let him get a tattoo for his birthday. There's an old lady who stands on the corner yelling at strangers all day. I think she's got bats in her belfry.See also: bats, belfry, have