English idiom: “When pigs fly”

When Pigs Fly is an English idiom that describes an impossible event, something that will never happen. In conversation, it is used sarcastically or to humorously express a lack of belief in something someone has said.

For example: a friend who wakes up late every morning, suddenly tells another friend that they will wake up early tomorrow and go for a run. The other friend could sarcastically reply, “Sure, that’ll happen when pigs fly.”

The idiom has been around in literature since the 1600s, and the early form of the expression was “Pigs fly in the air with their tails forward”. It was first recounted in 1616 by John Withal in his Dictionary for young beginners and it is said that the early form of the expression was used for 200 years as a sarcastic response to an overly-optimistic prediction made by someone.

The idiom was used then in the same way as it’s used today. One among many of the famous books using the modern version of the idiom is in Lewis Carol’s Alice’s Adventures in Wonderland.

Now that you’ve learned about this common English idiom, why not try it out with one of our Practicing English volunteers? Click “Contact Us” to schedule your appointment today!