An antiquated term for
insanity, madness. Belfry: the top of a bell tower on a church, where the
bell is housed. Often infested with bats, who enjoy the
darkness and seclusion of the place.
She's got
bats in the belfry, sqirrels in the attic, owls up in the
loft. She's apeshit, bughouse,
batty, mad as a march hare.