mad as a hatter
In real, traceable use. Part of the curated seed collection; community review is coming.
Meaning · English
Crazy or demented.
Where it’s used:
Used
American English
Examples
He's a very good fellow, but as mad as a hatter. He's called Madman, you know. And never was such a fellow for getting all sorts of rum things about him. He tamed two snakes last half, and used to carry them about in his pocket; and I'll be bound he's got some hedgehogs and rats in his cupboard now,
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 “mad as a hatter” mean?
Crazy or demented.
Is “mad as a hatter” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.