Source : Webster's Revised Unabridged Dictionary (1913)

Appropriateness \Ap*pro"pri*ate*ness\, n.
   The state or quality of being appropriate; peculiar fitness.
   --Froude.

Source : WordNet®

appropriateness
     n 1: appropriate conduct; doing the right thing [syn: {rightness}]
          [ant: {inappropriateness}]
     2: the quality of being specially suitable [ant: {inappropriateness}]