one card shy of a full deck
Not all there
Lacking full mental capacity or good sense—a colorful way to call someone stupid or crazy.
The image is of a deck of playing cards missing one, rendering it useless for most games.
Like similar expressions (not the sharpest tool in the shed, a few fries short of a Happy Meal), it softens the insult with humor: He's one card shy of a full deck if he thinks that plan will work.
- not the sharpest tool in the shedEuphemism for unintelligent
- not the brightest bulbLacking intelligence or wit
- eccentricityUnconventional behavior or nature
- quirkinessUnusual or unexpected trait
- out to lunchDistracted, unaware of surroundings
lights are on but nobody's home · oddness · deficient · off one's rocker · incomplete · unbalanced · loose cannon · bats in the belfry · irrationality · lacking · impaired · missing · flawed · partial · fragmentary · dim-witted · unconventionality · off the wall
one card shy of a full decksharp as a tack
Extremely intelligent and alert
sharp-minded · playing with a full deck · brilliant · genius · all there
one card shy of a full decksane
Mentally healthy, clearheaded
well-balanced · of sound mind · all there · stable · level-headed