un·think·able
ˌən-ˈthiŋ-kə-bəl
1
: not capable of being grasped by the mind
2
: being contrary to what is reasonable, desirable, or probable : being out of the question
un·think·abil·i·ty
¦ənˌthiŋkə¦bilətē
: the quality or state of being unthinkable
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Merriam-Webster unabridged



