unutterability means unutterableness. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Why “unutterability” is a great word
UNUTTERABILITY — [Noun] The quality or state of being impossible to express in spoken words. Formed within English by derivation from the adjective 'unutterable' (from the prefix 'un-' meaning 'not' + 'utterable') and the noun-forming suffix '-ity'. Unlike “ineffability,” which often cloaks the unspeakable in an aura of the sacred or sublime, or “inexpressibility,” which concerns any failure of communication, “unutterability” denotes a stark, specific failure of speech. It is the gasp that chokes off a confession, the mute horror of a recurring nightmare whose details dissolve upon waking, the perfect thought that evaporates an instant before it finds the tongue—a testament to the vast, private geography of experience that language can never fully colonize.
Etymology
From un- + utterability.
noun
- unutterableness
- Something that cannot be said.“The great Sun flames broader towards setting: one's heart flutters on the verge of dread unutterabilities.”