A term used to describe a person who is not all there. A person missing a marble or two - a few percentages off from being full blown retarded.
"I can't believe that guy just walked into that glass door - what is he...one short of a six pack?"
by D. Ferrel September 30, 2003
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Someone who lacks common sense. Not quite mentally competent.
You're one beer short of a six pack. You have no idea what you're talking about.
by Oldman. February 20, 2018
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