dumb as a box of rocks
In real, traceable use. Part of the curated seed collection; community review is coming.
Meaning · English
Very stupid.
Register: slang
Where it’s used:
Used
American English
Examples
The drummer in my friend's band is pretty hot, but he's dumb as a box of rocks. I hear he likes me, and I definitely don't want to date him—but is his stupidity any reason not to simply have sex with him? — Carla, Brooklyn, New York
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Common questions
What does “dumb as a box of rocks” mean?
Very stupid.
Is “dumb as a box of rocks” formal or informal?
dumb as a box of rocks is generally slang.