When pigs fly
Meaning
This idiom is used to express extreme skepticism or the belief that something will never happen.
Origin
The phrase "When pigs fly" captures the very essence of impossibility through a vivid, absurd image. While the exact moment of its birth is debated, the core idea traces back to an old Scottish proverb, "Pigs may whistle, but they have unco' [uncommon] mouths." Over time, the image evolved, with pigs attempting the even more improbable feat of flight. Its popularity soared in the 19th century, particularly through its use in literature to mock ludicrous claims and express utter disbelief, cementing the flying pig as the ultimate symbol of a never-to-be-seen event.
Examples
- My lazy brother said he'd clean his room this weekend, but I'll believe that when pigs fly.
- The manager promised us a pay raise, but we all know that's going to happen when pigs fly.