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. © 2015 Farlex, Inc, all rights reserved.