He has bats in his belfry if he thinks that will work.
have bats in one's belfry
idiomTo be crazy or eccentric.
Origin
first recorded 19th c.1899, from tendency of bats to fly around erratically, with “belfry” indicating “head, mind”.
Everyone thinks the old man has bats in his belfry because he talks to his garden plants every morning.
While his colleagues dismissed his radical theories as evidence that he had bats in his belfry, he remained convinced that his unconventional approach would eventually yield a breakthrough.
- 01
abound in one's own sense
To follow one’s own inclinations and opinions.
- 02
ace up one's sleeve
A surprise advantage of which others are not aware.
- 03
act one's age
To behave in a manner appropriate to one's age.
- 04
act one's age, not one's shoe size
Synonym of act one's age (“to behave in a mature manner; to avoid being childish”).
- 05
afraid of one's own shadow
Exceptionally timid.
- 06
air one's dirty laundry in public
To reveal one's sordid secrets to the public.
- 07
air one's dirty linen in public
Synonym of air one's dirty laundry in public.
- 08
albatross around one's neck
A characteristic, possession, associate, or previous deed that hinders one's ability to succeed.
Last updated July 12, 2026