The Collaborative International Dictionary of English v.0.48:

Dispossession \Dis`pos*ses"sion\, n. [Cf. F. d['e]possession.]
   1. The act of putting out of possession; the state of being
      dispossessed. --Bp. Hall.
      [1913 Webster]

   2. (Law) The putting out of possession, wrongfully or
      otherwise, of one who is in possession of a freehold, no
      matter in what title; -- called also ouster.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dispossession
    n 1: the expulsion of someone (such as a tenant) from the
         possession of land by process of law [syn: eviction,
         dispossession, legal ouster]
    2: freeing from evil spirits [syn: exorcism, dispossession]