(n) the quality of being improbable, Syn. improbableness, Ant. probability, Example:impossibility should never be confused with improbability; the improbability of such rare coincidences
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
n.; pl.Improbabilities [ Cf. F. improbabilité. ] The quality or state of being improbable; unlikelihood; also, that which is improbable; an improbable event or result. [ 1913 Webster ]