The Collaborative International Dictionary of English v.0.48:

dissipate \dis"si*pate\ (d[i^]s"s[i^]*p[=a]t), v. t. [imp. & p.
   p. Dissipated; p. pr. & vb. n. Dissipating.] [L.
   dissipatus, p. p. of dissipare; dis- + an obsolete verb
   sipare, supare. to throw.]
   1. To scatter completely; to disperse and cause to disappear;
      -- used esp. of the dispersion of things that can never
      again be collected or restored.
      [1913 Webster]

            Dissipated those foggy mists of error. --Selden.
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            I soon dissipated his fears.          --Cook.
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            The extreme tendency of civilization is to dissipate
            all intellectual energy.              --Hazlitt.
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   2. To destroy by wasteful extravagance or lavish use; to
      squander.
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            The vast wealth . . . was in three years dissipated.
                                                  --Bp. Burnet.

   Syn: To disperse; scatter; dispel; spend; squander; waste;
        consume; lavish.
        [1913 Webster]