when pigs fly

W

when pigs fly (idiom)
/wɛn pɪɡz flaɪ/

Meaning

• Impossible or highly unlikely to happen.
• “When pigs fly” means that something will never happen. It expresses the impossibility of an event or situation occurring.
• The phrase is used humorously to denote skepticism or disbelief in the likelihood of a particular event taking place.
• It can also imply that something is extremely unlikely or improbable, to the point of being impossible.
• The idiom serves as a sarcastic response to overly optimistic or unrealistic expectations.
• It is typically used in informal settings to emphasize the sheer impossibility of an event.

Variants

• pigs may fly
• pigs might fly
• flying pig

Example Sentences

1. She’ll agree to go camping when pigs fly; she hates the outdoors.
2. The boss will give us a day off when pigs fly.
3. I’ll believe you can finish that project on time when pigs fly.
4. He said he’d quit smoking, but that’ll happen when pigs fly.
5. They’ll finish the construction on schedule when pigs fly.
6. She’ll start arriving on time when pigs fly; she’s always late to every meeting.
7. My brother said he’ll start cooking healthy meals every day—maybe when pigs fly.
8. Do you think they’ll lower the price of those concert tickets? Pigs may fly!
9. Emma said she’d consider moving to the country, but pigs might fly before that happens.

Origin and History

The idiom “when pigs fly” has a rich history that spans centuries, with roots in early literature and proverbs. Its enduring popularity can be attributed to its vivid imagery and universal appeal, transcending cultural and linguistic boundaries. Its origins are often linked to a centuries-old Scottish proverb, “If a pig had wings, it could fly,” suggesting the improbability of certain events. There are several theories and historical references that offer insight into its origins.

Early Recorded Instances

In literature, François Rabelais’s 16th-century work, Gargantua and Pantagruel, features a vivid depiction of a flying pig. In the Fourth Book (1552), during Pantagruel’s battle with the Chitterlings, a massive, winged pig appears:

“From the north, a big, fat, gray pig came flying up, with wings as long and wide as those of a windmill… Its eyes were as red and flaming as those of a carbuncle.”

This humorous and exaggerated image was used to represent something highly unlikely or laughably implausible. While the phrase “when pigs fly” is not used directly, the visual of flying pigs was already established in literature as a way to mock impossible ideas.

Again, a similar phrase appeared in the early 17th century. In 1616, English lexicographer John Withals included the expression “pigs fly in the ayre with their tayles forward” in his Latin-English dictionary titled A Shorte Dictionarie for Yonge Begynners, indicating the notion of impossibility. Another early reference appears in the Scottish proverb “and Pigs May Fly Away with the Tod,” found in a 1639 compilation. This phrase was used to describe something highly unlikely to occur.

Reference in Ben Jonson’s 1616 Play: Fitzdottrel and Pug

Another notable early reference comes from Ben Jonson’s 1616 play, The Devil is an Ass. In Act 1, Scene 1, the character Fitzdottrel, a foolish nobleman, engages in a conversation with Pug, a minor devil. During their exchange, Fitzdottrel uses a line that sarcastically implies something will happen “when pigs fly,” expressing disbelief in the possibility of an event. Although the exact wording differs from the modern phrasing, the meaning mirrors the contemporary idiom—highlighting something absurd or impossible. This reference illustrates that the idea behind the phrase was already present in early 17th-century English literature.

Some modern sources claim that the idiom first appeared in this play. However, there is no clear evidence that the phrase—either in its current form or a close variant—appeared in this play. Such evidence has led scholars and researchers to question the validity of this attribution.

Literary Appearances

The expression gained further traction in the 19th century. Notably, Lewis Carroll popularized a variation of the phrase in his 1865 novel “Alice’s Adventures in Wonderland,” where the Duchess remarks, “Just about as much right as pigs have to fly.” This whimsical usage contributed to the idiom’s spread in English literature. Additionally, the phrase “pigs might fly” was noted in various publications, including Bell’s Life in London in 1834 and The Liverpool Mercury in 1849, indicating its established presence in the language​.

Possible Cultural Influences

Pigs have historically been significant in various cultures, often symbolizing wealth, fertility, and abundance. In Greek mythology, pigs were associated with the followers of Dionysus, while in Norse mythology, wild boars represented strength. The association of pigs with grounded, earthly qualities may have contributed to the absurdity of the idea that they could fly, thereby reinforcing the idiom’s meaning of impossibility.

Variations and Similar Expressions

The phrase “when pigs fly” has numerous equivalents in other languages, reflecting the universal concept of impossibility. For instance, the French say “quand les poules auront des dents” (when hens have teeth), and the Spanish use “cuando las ranas críen pelo” (when frogs grow hair). These expressions highlight the global nature of the concept.

Modern Usage and Cultural Impact

In modern times, the phrase “when pigs fly” continues to be used humorously and sarcastically to express skepticism. Its vivid imagery makes it a memorable way to convey disbelief. The phrase also inspired creative expressions like “Pigasus,” a winged pig character, used by author John Steinbeck as a personal symbol of aspiring beyond one’s limitations​.

Synonyms

1. when hell freezes over
2. not in a million years
3. that will be the day
4. over my dead body
5. fat chance

About the Author

Elena Jones holds a PhD in Education from Harvard University. She has extensive experience teaching at both the K–12 and university levels, with a particular focus on English as a Second Language. Elena has dedicated her career to advancing educational practices, and she has contributed to numerous educational journals.

Animal