knock into a cocked hat

Idioms

Debunk, render useless or unbelievable. For example, His findings knocked our theory into a cocked hat. This expression alludes to a style of hat with the brim turned up on three sides—the three-cornered (tricorne) hat worn by officers in the American Revolution—giving it a distorted look. [Early 1800s]

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023