The Collaborative International Dictionary of English v.0.48:

Disunite \Dis`u*nite"\, v. t. [imp. & p. p. Disunited; p. pr.
   & vb. n. Disuniting.]
   1. To destroy the union of; to divide; to part; to sever; to
      disjoin; to sunder; to separate; as, to disunite particles
      of matter.
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   2. To alienate in spirit; to break the concord of.
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            Go on both in hand, O nations, never be disunited,
            be the praise . . . of all posterity! --Milton.
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