The Collaborative International Dictionary of English v.0.48:

Passivity \Pas*siv"i*ty\, n. [Cf. F. passivit['e].]
   1. Passiveness; -- opposed to activity. --Jer. Taylor.
      [1913 Webster]

   2. (Physics) The tendency of a body to remain in a given
      state, either of motion or rest, till disturbed by another
      body; inertia. --Cheyne.
      [1913 Webster]

   3. (Chem.) The quality or condition of any substance which
      has no inclination to chemical activity; inactivity.
      [1913 Webster]

WordNet (r) 3.0 (2006):

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