In English, we have lots of creative and colourful ways of saying that someone is not very smart! It’s not very nice to call someone ‘dumb’ or ‘stupid’, so in English we have a lot of funny expressions to use instead!

1) He’s not the sharpest tool in the shed!

I used this expression in the listening lesson “The Worst Bus Ride. Ever!”

There are many other versions of this expression:

Someone is …
…not the brightest crayon in the box
…not the brightest bulb in the chandelier
…not the sharpest knife in the drawer
…not the brightest star in the sky.
…not the brightest bulb on the Christmas tree.
…not the quickest bunny in the forest

Notice that they all have the same form:

[Someone] is not the [superlative] __________ in / on the ____________

These are all different ways of saying: [Someone] is not the smartest person in the world!

2) He’s one fry short of a Happy Meal!

This expression means that the person’s mind it not all there or complete. It means they’re a few brains cells short of a complete, active brain! Their brain is missing something, and therefore, they’re not that smart!

[‘A Happy Meal’ is what children can get at McDonald’s: a hamburger, a drink, french fries and a toy.]

Other versions:

Someone is…
…one crayon short of a box
…two pennies short of a nickel
…a few colors short of a rainbow.
…a few sandwiches short of a picnic
…a few cards short of a full deck
…a few peas short of a casserole
…a few clowns short of a circus
…a few players short of a team.

Similar expressions:

He’s missing a few buttons on his remote control.
He doesn’t have all the chairs at the table.

3) The elevator doesn’t go to the top floor.

This expression is also a way of saying that someone is slighty crazy and lacking common sense, in addition to not being very smart!

4) The light is on but nobody’s home.

This expression is a way of saying that someone is very, very [mentally] slow.

5) Somewhere there’s a village missing its idiot.

The “village idiot” is a very common character in English. It’s an informal expression used to describe someone in a village [group, community, town, city, country, etc.] who is really quite stupid and whose behaviour is quite bizarre!

NOTE: This expression should only be used in extreme circumstances, such as your worst enemy! Calling someone “an idiot” is not very nice.

Do you have any creative expressions in your language to say someone is not very smart?