When Sonny was in grammar school they taught him that “stupid” was a bad word. I agree. You absolutely should not walk up to someone and say “You’re stupid.” But there are times when situations, actions, and, yes, other people just are not smart. So here’s what you can say to avoid using that horrible, horrible word.
First there’s the inevitable comparison to the heavy, inanimate object:
You’re as dumb as a sack of hammers.
You’re as dumb as a box of rocks.
You’re as dumb as a stump.
Then there are the references to the not smart person’s rear end:
You don’t know your ass from a hole in the ground.
You don’t know your ass from your elbow.
You couldn’t find your ass with both hands in your back pockets.
I don’t really see any reason to insult poor, defenseless animals by comparing them to humans, but here are the animal references:
You’re as dumb as an ox.
Even a blind hog can find an acorn every now and then.
You’re not the quickest bunny in the forest.
And here are a few more just for good measure:
You’re dumb as dirt.
You’re a bubble off plumb.
The lights are on but nobody’s home.
You’re not the sharpest knife in the drawer.
You’re not the brightest bulb in the bulb box.
Somewhere there’s a village missing its idiot.
So remember, children, it’s not smart to call someone “stupid.” Especially when you have options. And smart people always have options.