The Collaborative International Dictionary of English v.0.48:

Properness \Prop"er*ness\, n.
   [1913 Webster]
   1. The quality of being proper.
      [1913 Webster]

   2. Tallness; comeliness. [Obs.] --Udall.
      [1913 Webster]

WordNet (r) 3.0 (2006):

properness
    n 1: correct or appropriate behavior [syn: propriety,
         properness, correctitude] [ant: improperness,
         impropriety]