dumber than a box of rocks
Extremely low intelligence
Dumber than a box of rocks describes extreme stupidity—the implication being that rocks have no intelligence at all, and the person in question has even less.
The phrase is folksy and dismissive: He's dumber than a box of rocks if he thinks that'll work.
Variants include dumb as a box of rocks and dumb as a rock.
- unintelligentLacking cognitive ability
- dumb as a bag of hammersExtremely unintelligent person
- dumb as a doorknobExtremely unintelligent person
- brainlessDevoid of intelligence
- foolishLacking good sense
simple-minded · dimwitted · slow-witted · dull as dishwater · ignorant · not the sharpest tool in the shed · mindless · stupid · vacuous · obtuse · thick as a brick · idiocy · clueless · lights are on but nobody's home · harebrained · dumb as a post · sharp as a bowling ball · unwise
dumber than a box of rocksgenius
Person of rare brilliance
brilliant · sharp as a tack · smart as a whip · Einstein · intellectual
dumber than a box of rockssharp as a tack
Extremely intelligent and alert
smart as a whip · quick on the uptake · bright as a button · nobody's fool · wicked smart