you must have rocks in your head
Proposed by a contributor, not yet supported by evidence.
Meaning · English
To be foolish or crazy
Literally: having rocks in one's head
Where it’s used:
Used
Widespread English
Sources & notes
Listed on Wikipedia “List of proverbial phrases” (CC BY-SA 4.0, retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-30; pending editor spot-check.
Common questions
What does “you must have rocks in your head” mean?
To be foolish or crazy Literally: having rocks in one's head
Is “you must have rocks in your head” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.