- beyond the ability to understand or imagine; inconceivable
- so extreme, foul, etc. as to be unfit to be imagined or considered: unthinkable war crimes
See unthinkable in American Heritage Dictionary 4
- Impossible to imagine; inconceivable: an unthinkable amount of money.
- Contrary to what is plausible or probable: That this project would achieve ultimate success was unthinkable at the time.
- Not to be thought of or considered; out of the question: Raising taxes was politically unthinkable.
- un·thinkˌa·bilˈi·ty, un·thinkˈa·ble·ness noun
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