10 Best Phrases for Something That Is Impossible

Idioms are a lot of fun to play around with. If you have an idiom set up for every situation, you will show people that you mean business with how well you grasp the English language. This article will explore good idioms to describe something that is impossible.

The preferred alternatives are “when hell freezes over,” “when pigs fly,” and “on the first of never.” Each idiom highlights the impossibility or unlikelihood of a task or goal. It shows that you do not believe something will change unless one of the impossible situations is met.

When Hell Freezes Over

“When hell freezes over” is one of the best metaphors to show that something is impossible. It works really well because hell is described as a boiling place where damned souls go to burn for eternity.

Naturally, it is hard to freeze boiling things. Imagine trying to freeze fire. You wouldn’t have an easy time doing it. That’s what this idiom is trying to suggest, and it’s why it works so well to show that something is impossible.

• Oh, that’s not going to happen, man! Maybe when hell freezes over, but I don’t think you’ve got it in you to complete that.
• When hell freezes over, Dave might start talking to you. Until then, maybe it’s time for you to look elsewhere for other options.
• I’m certain something like this will happen when hell freezes over. Otherwise, I don’t see much hope in you getting it completed.

When Pigs Fly

“When pigs fly” is another great metaphor you can use. It works really well, and it’s really popular with native speakers because of how old it is. Everyone knows what it means when this idiom is used.

The idea is that pigs can’t fly. Technically, you could pick any land or sea-based animal that cannot fly. However, “pigs” are used in this metaphor for imagery, and people remember that it means something will never happen.

• We can date each other when pigs fly. The moment you see a pig flying way up in the sky, you give me a call to let me know.
• When pigs fly, she’ll be there for me. She’s one of the least caring people I know. So, you can understand my skepticism.
• I’m not sure something like that will ever happen. Maybe when pigs fly, but even that is asking a lot for the outcome you expect.

On The First Of Never

“On the first of never” is a good idiom you can use. It sets up false hope initially by saying, “on the first of.” This makes people believe you’re going to give them a specific date. Following that with “never” shows that it will never come true.

Obviously, people expect you to say “on the first of June” (or any month after “of”). Using “never” is a good way to crush their belief or spirit here.

• On the first of never, I’ll talk to you about it. Until that day, I suggest you consider different methods to cope with the split.
• I’m not sure they’ll be able to do this. Not even on the first of never. It just doesn’t seem to make any sense.
• I told them that it would happen on the first of never. They’re still waiting for it to come true. I’ll admit that I admire their blind faith.

It Will Be A Cold Day In Hell When

“It will be a cold day in hell when” is a great idiom you can use to show that something is impossible. It plays on the idea that hell is too hot to be cold again, which is a common trend when looking at impossible metaphors like this.

Again, this is a very popular one amongst native speakers. It’s also very harsh, so you need to make sure you use it in a way that isn’t trying to hurt someone’s feelings.

• It will be a cold day in hell when you finally realize that you’re in the wrong here. I don’t think I’ve ever met anyone like you.
• It’ll be a cold day in hell when I change my stance on this. I’m pretty firm on it, and I don’t think it’s fair for you to test me.
• It will be a cold day in hell when this happens again. I don’t have a lot of hope for it to come true. Sorry about that.

Not In A Million Years

“Not in a million years” is more of a statement than an idiom, but it works well. You can use this to show that something will never happen. “A million years” works here to show that you have no faith in something coming true.

This is a great phrase to use if you want to shut someone down quickly. It shows that you will never change your mind about something and believe that it will never be possible.

• Oh, no. Not in a million years will I ever go out with you. I’m sorry, but I just don’t think we’re all that compatible right now.
• Nope. Not in a million years. You seem to think that you’re entitled to this with me, but I don’t think things work like that.
• I’m sorry, but I have to say not in a million years. I don’t believe you have the correct work ethic to get this done.

Not A Chance

“Not a chance” is another statement that works well here. It might not be a direct idiom, but it allows you to express your disagreement over the possibility that something might happen.

“Not a chance” means that you do not believe something will ever be possible.

If you want to extend the idiom, it’s very common for people to say, “not a chance in hell.” If you prefer that version, you should use it.

• Oh, not a chance in hell! I’m sorry, but I don’t buy into any of that nonsense. It just doesn’t make sense to me.
• No way! Not a chance! I don’t see it happening, and I’d prefer it if you stopped asking me for my opinion.
• Not a chance, man! You’re never going to be able to pull a bird like that. It simply won’t happen. Don’t even try.

When The Cows Come Home

“When the cows come home” is a great idiomatic expression that shows that something is unlikely or impossible. It shows that you will be waiting for something to happen for a very long time, indicating that it will never come true.

• I’ll believe you when the cows come home. I appreciate that you believe in yourself, but it’ll take more than that for me.
• She said that she’d agree with me when the cows come home. I suppose that means she doesn’t trust a word of it.
• I’m not going to say anything on this matter. At least not until the cows come home. I think it’s only fair I wait until then.

Don’t Hold Your Breath

“Don’t hold your breath” is a great alternative because it indicates that something will never happen. If you were to hold your breath while waiting for something to happen, you would die before you saw it.

The indication here is that you cannot hold your breath for long enough to see something happen. If someone doesn’t believe that something is possible, they’ll use this idiom to remind you.

• Don’t hold your breath. I’m not planning on changing my mind about this anytime soon. You have to deal with that.
• I’m sorry, but don’t hold your breath. I know how things like these go. It won’t end in the way you seem to think it will.
• I wouldn’t hold your breath. She’s already made her feelings clear. You’re chasing after an impossible dream right now.

Once In A Blue Moon

“Once in a blue moon” is another great synonym that shows something does not work or is impossible. A “blue moon” is a very rare occurrence which suggests that something cannot happen when you expect it to.

• It’ll happen once in a blue moon, so good luck with that. I’m sure you can figure something out to change those odds.
• Oh, yeah! Once in a blue moon, Darren actually shows up to work on time. It’s amazing when he manages to pull it off.
• They can only do it once in a blue moon, which is why it’s impossible to see it happen. It’s a really private event, to be fair.

In A Month Of Sundays

“In a month of Sundays” is an interesting idiom that doesn’t get used much. It works well because it refers to something being impossible unless a specific month of only Sundays takes place. Since this is impossible, it indicates that the thing is impossible too.

• I’m not saying that I don’t trust him. I’m just saying that he won’t be able to do this in a month of Sundays. He hasn’t got what it takes.
• In a month of Sundays, I’ll never see him change his mind. I know he believes in this too much, and that’s such a shame.
• It’s only going to come true in a month of Sundays. I suppose you could wait until that time to change your stance on it.