The Collaborative International Dictionary of English v.0.48:

Deraignment \De*raign"ment\, Derainment \De*rain"ment\, n. [See
   Darraign.]
   1. The act of deraigning. [Obs.]
      [1913 Webster]

   2. The renunciation of religious or monastic vows. [Obs.]
      --Blount.
      [1913 Webster]