be a/one beer short of a six-pack

derogatory To be unintelligent or of questionable mental capacity. One of many different forms and variations of the phrase (for example, "a few sandwiches shy of a picnic," "one card shy of a full deck," etc.). Every time Paul tells me about his latest conspiracy theory, I can't help thinking that he's one beer short of a six-pack. He says he's going to start a business selling bees as pets. I think he's one beer short of a six-pack. Anyone who would go out in a blizzard like this is a beer short of a six-pack.