|1.||when hell freezes over|
signifies that something will never, ever happen.
1: so when will the Bengals win the Super Bowl?
2: when hell freezes over, that's when.
|2.||when hell freezes over|
Idiomatic expression used to describe an event or scenario that is so unlikely that it will likely never occur.
Q: Dude, I'm tired of the beach. Wanna go and ride that fake, plastic wave that they setup at Wal-Mart?
Q: Right on! Let's roll!
A: Hold on, I'd rather do that when hell freezes over. You stupid nincompoop.