Source : Webster's Revised Unabridged Dictionary (1913)

Nastiness \Nas"ti*ness\, n.
   The quality or state of being nasty; extreme filthness;
   dirtiness; also, indecency; obscenity.

         The nastiness of Plautus and Aristophanes. --Dryden.

Source : WordNet®

nastiness
     n 1: a state characterized by foul or disgusting dirt and refuse
          [syn: {filth}, {filthiness}, {foulness}]
     2: malevolence by virtue of being malicious or spiteful or
        nasty [syn: {cattiness}, {bitchiness}, {spite}, {spitefulness}]
     3: the quality of being unpleasant; "I flinched at the
        nastiness of his wound" [ant: {niceness}]