52 cards short of a deck, and playing with the jokers.
A few beers short of a six-pack.
A few clowns short of a circus.
A few crumbs short of a crouton.
A few fries short of a happy meal.
All foam, no beer.
All the marbles aren’t round.
Am I getting smart with you? How would you know?
An experiment in Artificial Stupidity.
An intellect rivaled only by garden tools.
Antenna doesn’t pick up all the channels.
Asks to have his/her pizza sliced in 4 pieces because he/she can’t
eat 8.Belt doesn’t go through all the loops
Body by Fisher, brains by Mattel.
Book is full of blank pages.
Brilliant as a black-hole in space.
Brilliant as a burnt-out light bulb.
Bubble off of plumb.
Cheese slid off of his cracker.
Christmas tree doesn’t have an angel on the top.
Cornbread didn’t get baked.
Couldn’t find his/her way out of a wet paper bag.
Couldn’t pour water out of a boot with instructions on the heel.
Dealing with a full deck of jokers.
Dealing with a half a deck.
Dip stick doesn’t quite reach the oil.
Doesn’t have all his cornflakes in one box.
Doesn’t have all his dogs on one leash.
Doesn’t have both oars in the water.
Doesn’t know much, but leads the league in nostril hair.
Driving with the engine shut off.
Dumb as fertilizer, but not as useful
Dumber than a box of hair.
Dumber than a box of rocks.
During evolution his ancestors were in the control group.
Elevator doesn’t reach the top floor.
Fell out of the stupid tree and hit every branch on the way down.
Forgot to pay the brain bill.
From the shallow end of the gene pool.
Gates are down, the lights are flashing, but the train isn’t coming.
Half bubble off.
Has an IQ of 2, but it takes 3 to grunt.
Has reached the bottom of the heap and is now digging.
Having a blond moment.
He/she is depriving a village of an idiot.
He/she isn’t stupid, he/she’s ignorantly endowed.
High priority recipient when they start brain transplants.