eat your hat

eat (one's) hat

A humorous action that one will allegedly take if something very unlikely happens. Kevin is always late, so if he actually shows up on time, I'll eat my hat.
See also: eat, hat

eat your hat

mainly BRITISH, OLD-FASHIONED
If you say that you will eat your hat if a particular thing happens, you mean that you do not believe that it will happen. I will eat my hat if the Social Democrats get in at the next general election. He has promised to eat his hat if he is wrong.
See also: eat, hat