Why this word is great
UNTHINKABILITY — [Noun] The state of being impossible to conceive, imagine, or accept, whether due to cognitive limits or moral revulsion. From unthinkable ("not able to be conceived or imagined") + -ity (suffix forming nouns denoting a state or condition). Unlike "impossibility" (which deals with physical or logical constraints) or "inconceivability" (which focuses on mental representation alone), unthinkability carries the weight of refusal—a mind recoiling from an idea as much as failing to grasp it. It is the blank space where a thought should be, the silence that follows an unspeakable suggestion, the instinctive shudder at the notion of betraying one’s deepest loyalties. Some things are not merely hard to think; they must not be thought.