Source : Webster's Revised Unabridged Dictionary (1913)

Inconceivability \In`con*ceiv`a*bil"i*ty\, n.
   The quality of being inconceivable; inconceivableness.

         The inconceivability of the Infinite.    --Mansel.

Source : WordNet®

inconceivability
     n : the state of being impossible to conceive [syn: {inconceivableness}]