Source : Webster's Revised Unabridged Dictionary (1913)

Preoccupy \Pre*oc"cu*py\, v. t. [imp. & p. p. {Preoccupied}
   (-p[=i]d); p. pr. & vb. n. {Preoccupying}.] [Cf. F.
   pr['e]occuper. See {Preoccupate}, {Occupy}.]
   1. To take possession of before another; as, to preoccupy a
      country not before held.

   2. To prepossess; to engage, occupy, or engross the attention
      of, beforehand; hence, to prejudice.

            I Think it more respectful to the reader to leave
            something to reflections than to preoccupy his
            judgment.                             --Arbuthnot.

Source : WordNet®

preoccupy
     v 1: engage or engross the interest or attention of beforehand or
          occupy urgently or obsessively; "His work preoccupies
          him"; "The matter preoccupies her completley--she cannot
          think of anything else"
     2: occupy or take possession of beforehand or before another or
        appropriate for use in advance; "the army preoccupied the
        hills"
     [also: {preoccupied}]