one egg short of a dozen

one egg short of a dozen

A derogatory phrase meaning not very intelligent or of questionable mental capacity. He says he's going to start a business selling bees as pets—I think he may be one egg short of a dozen. Every time Paul tells me about his latest conspiracy theory, I can't help thinking that he's one egg short of a dozen.
See also: dozen, egg, of, one, short
Farlex Dictionary of Idioms.
See also:
  • a few eggs short of a dozen
  • bananas
  • a few bananas short of a bunch
  • a few cards short of a (full) deck
  • a few cards shy of a (full) deck
  • be a waste of space
  • carry a Chinaman on (one's) back
  • have a Chinaman at (one's) neck
  • have a Chinaman on (one's) back
  • Chinaman's chance, he hasn't a/not a