{not|never} in a (thousand|million|billion) years
1
used to say that the chances of something happening or being true are very slim
The phrase "not in a million years" is an idiom used to express extreme certainty that something will never happen. The origin of this phrase is not precisely documented, but it likely emerged from the idea that a million years is an incredibly long time, making the occurrence of a particular event extremely unlikely.
- I would not go back to that restaurant in a million years, the service was terrible.
- She would never forgive him in a billion years after what he did.
- Not in a thousand years did I expect him to actually show up on time.
- He would not take that job in a billion years, it pays far too little.
- That cat is never in a million years going to accept the new puppy.