I’ll eat my hat is an idiom that is hundreds of years old. We will examine the meaning of the common idiom I’ll eat my hat, where it came from, and some examples of its idiomatic usage in sentences.
I’ll eat my hat is an exclamation that means one is certain of a fact or an outcome or that one is confident in one’s opinion. The expression I’ll eat my hat has been in use at least since the latter-1700s, though it’s popularity swelled in the mid-1800s. There are two dubious theories for the origin of the phrase I’ll eat my hat. The first traces the origin of the phrase to Charles II and the phrase “I’ll eat Old Rowley’s hat,” a reference to an unfortunate nickname given to Charles II. However, the term isn’t seen until well after Charles II’s rein. The second origin story traces the idiom I’ll eat my hat to a certain savory pastry popular in the 1400s called a hatte. However, the idiom was not seen until 300 years later. What is known is that Charles Dickens used the expression in The Pickwick Papers in 1837: “If I knew as little of life as that, I’d eat my hat and swallow the buckle whole.” The term became popular after that time.
For, as more than one accountant and Tory MP has said since the Office of Tax Simplification called for it to be aligned with income tax this week: “If he does that, I’ll eat my hat.” (Evening Standard)
“Also, I’ll eat my hat if we don’t see Instant Pot deals ― they are exceptional and ubiquitous on and around Prime Day and Black Friday.” (Huffington Post)
“If we are even remotely back into doing anything in 2020,” I thought, “I’ll eat my hat.” (San Francisco Classical Voice)