The Collaborative International Dictionary of English v.0.48:

Exaction \Ex*ac"tion\, n. [L. exactio: cf. F. exaction.]
   1. The act of demanding with authority, and compelling to pay
      or yield; compulsion to give or furnish; a levying by
      force; a driving to compliance; as, the exaction to
      tribute or of obedience; hence, extortion.
      [1913 Webster]

            Take away your exactions from my people. --Ezek.
                                                  xlv. 9.
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            Daily new exactions are devised.      --Shak.
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            Illegal exactions of sheriffs and officials.
                                                  --Bancroft.
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   2. That which is exacted; a severe tribute; a fee, reward, or
      contribution, demanded or levied with severity or
      injustice. --Daniel.
      [1913 Webster]

WordNet (r) 3.0 (2006):

exaction
    n 1: act of demanding or levying by force or authority;
         "exaction of tribute"; "exaction of various dues and fees"