have bats in one’s belfry

have bats in (one's) belfry

To be crazy; to act, think, or behave in a foolish or nonsensical manner. Tommy has 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 might have bats in her belfry.
See also: bats, belfry, have
Farlex Dictionary of Idioms.

have bats in one’s belfry

(...ˈbɛlfri)
tv. to be crazy. (see also bats. Have got can replace have.) Pay no attention to her. She has bats in her belfry.
See also: bats, belfry, have
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • have bats in (one's) belfry
  • have bats in belfry
  • have bats in the belfry
  • have got bats in (one's) belfry
  • bats in one's belfry, have
  • belfry
  • have toys in the attic
  • have a few kangaroos loose in the top paddock
  • have kangaroos in (one's)/the top paddock
  • have kangaroos in the top paddock