You are sharp as a wet sack of marbles

Lacking the basic intelect of being able to breathe.

You are sharp as a wet sack of marbles.

by John Joe September 20, 2012

Sharp as a mop

A person who may not be astute but has a seemingly purposeful presence. The person may be useful but doesn't have an external awareness. A mop serves a purpose but is not a intelligectually significant.

You're sharp as a mop.

by urban-grl June 25, 2016

Sharp as a Beach Ball

Not too bright and certainly not sharp!
Usefully juxtaposed to something really sharp.
The opposite of "sharp as a razor" - clearcut and incisive.

That guy is as sharp as a beach ball - he didn't even realise the girls were teasing him when they fell on the floor laughing! He was well taken in!

by Brian Butterly February 13, 2007

sharp as a spoon

a person who is not too clever

your as sharp as a spoon

by mob January 13, 2004

sharp as a sphere

Someone who is not too sharp, smart, clever, or anywhere near brainiac status.

Gill: Oh, I see you got your laces into your new shoes, Kev. Good Job!!
Kev: It was no problem, Gill. I remembered from last time.
Gill: You sure are as sharp as a sphere!
Kev: You bet I am! Now help me tie my new shoes.

by von groovy July 21, 2017

sharp like a rock

really stupid

You know Kate, she's sharp like a rock.

by zachwolff October 15, 2003

Sharp as a whip

Probably a bastardization of smart as a whip, meaning unusually intelligent or quick witted.
Often changed for comic effect by substituting 'whip' for an object with no edges.

"Although Arthur looks like a clueless dork, he's as sharp as a whip and completely in control."
"As sharp as chewed gum, more like!"

by Eyeyambob July 27, 2013