The Collaborative International Dictionary of English v.0.48:

Disassociate \Dis`as*so"ci*ate\, v. t. [imp. & p. p.
   Disassociated; p. pr. & vb. n. Disassociating.]
   To disconnect from things associated; to disunite; to
   dissociate. --Florio.
   [1913 Webster]