Improbability :: Improbability (n.) The quality or state of being improbable; unlikelihood; also, that which is improbable; an improbable event or result..
Improbable :: Improbable (a.) Not probable; unlikely to be true; not to be expected under the circumstances or in the usual course of events; as, an improbable story or event..
Inscribable :: Inscribable (a.) Capable of being inscribed, -- used specif. (Math.) of solids or plane figures capable of being inscribed in other solids or figures..