Not pulling a full wagon.
Not the brightest star in the sky.
The lights are on but no one’s home.
Not the brightest bulb in the box.
A few screws short of a hardware store.
Not the sharpest knife in the drawer.
A few cards short of a full deck.
A few fries short of a Happy Meal.
About as sharp as a marble.
Only has one oar in the water.
Smart as a bag of rocks.
A hamburger short of picnic.
The elevator doesn’t go all the way to the top floor.