the unthinkable
noun /ði ˌʌnˈθɪŋkəbl/
/ði ˌʌnˈθɪŋkəbl/
[singular]- a thing that is impossible to imagine or accept
- Suddenly the unthinkable happened and he drew out a gun.
- The time has come to think the unthinkable (= consider possibilities that used to be unacceptable).