Source : Webster's Revised Unabridged Dictionary (1913)

Anxiousness \Anx"ious*ness\, n.
   The quality of being anxious; great solicitude; anxiety.

Source : WordNet®

anxiousness
     n 1: a relatively permanent state of anxiety occurring in a
          variety of mental disorders [syn: {anxiety}]
     2: a feeling of mild anxiety about possible developments [syn:
        {disquiet}]