The Collaborative International Dictionary of English v.0.48:

Disinthrall \Dis`in*thrall"\, v. t. [imp. & p. p.
   Disinthralled; p. pr. & vb. n. Disinthralling.] [Pref.
   dis- + inthrall. Cf. Disenthrall.]
   To free from thralldom; to disenthrall. [Written also
   disinthral.]
   [1913 Webster]