The Collaborative International Dictionary of English v.0.48:

Interdict \In`ter*dict"\, v. t. [imp. & p. p. Interdicted; p.
   pr. & vb. n. Interdicting.] [OE. entrediten to forbid
   communion, L. interdicere, interdictum. See Interdict, n.]
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   1. To forbid; to prohibit or debar; as, to interdict
      intercourse with foreign nations.
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            Charged not to touch the interdicted tree. --Milton.
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   2. (Eccl.) To lay under an interdict; to cut off from the
      enjoyment of religious privileges, as a city, a church, an
      individual.
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            An archbishop may not only excommunicate and
            interdict his suffragans, but his vicar general may
            do the same.                          --Ayliffe.
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