dumber than a rock
Lacking all intelligence
Dumber than a rock describes someone of extremely low intelligence—so stupid they compare unfavorably to an inanimate object.
The phrase emphasizes that rocks, being incapable of thought, set a remarkably low bar: He's dumber than a rock if he thinks that'll work.
Sometimes varied with other objects: dumber than a box of rocks, dumber than a bag of hammers.
- brain-deadIrreversibly without consciousness
- not the sharpest tool in the shedEuphemism for unintelligent
- cluelessLacking any understanding
- thick as a brickHopelessly slow mentally
- airheadFoolish, flighty person
lights are on but nobody's home · sharp as a marble · dimwit · nincompoop · one brick shy of a load · slow on the uptake · empty-headed · dull as dishwater · pea-brained · flat as a pancake · scatterbrained · bird-brained · bird-brained
dumber than a rockgenius
Person of rare brilliance
brilliant · sharp as a tack · Einstein · smart as a whip · intellectual
dumber than a rockbrilliant
Intensely bright or gifted
gifted · talented · exceptional · remarkable · impressive
dumber than a rockcompliment
Words expressing approval
flattery · praise · high praise · glowing review · admiration
dumb, dumber, dumbest, dumbly, dumbness, rock, rocks, rocky, rockier