Con*ceiv"a*ble*ness

from The Collaborative International Dictionary of English v.0.48

Conceivable \Con*ceiv"a*ble\, a. [Cf. F. concevable.]
   Capable of being conceived, imagined, or understood. "Any
   conceivable weight." --Bp. Wilkins.
   [1913 Webster]

         It is not conceivable that it should be indeed that
         very person whose shape and voice it assumed.
                                                  --Atterbury.
   -- {Con*ceiv"a*ble*ness}, n. -- {Con*ceiv"a*bly}, adv.
   [1913 Webster]