eat my hat

People say this when they don't believe that something is going to happen e.g. 'If he passes that exam, I'll eat my hat!'

(UsingEnglish.com)

marianita123 What does the expression "eat my hat" mean?

It's almost always "I'll eat my hat", and it's almost always preceded by an if-clause.

If my wife wins a NASCAR race this year, I'll eat my hat.
If the problem of poverty in the world is solved in the next five years, I'll eat my hat.
If Assad turns over all his chemical weapons i

Thanks!