The Collaborative International Dictionary of English v.0.48:

Passiveness \Pas"sive*ness\, n.
   The quality or state of being passive; unresisting
   submission.
   [1913 Webster]

         To be an effect implies passiveness, or the being
         subject to the power and action of its cause. --J.
                                                  Edwards.
   [1913 Webster]

WordNet (r) 3.0 (2006):

passiveness
    n 1: submission to others or to outside influences [syn:
         passivity, passiveness]
    2: the trait of remaining inactive; a lack of initiative [syn:
       passivity, passiveness]