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.]
   [1913 Webster]
   1. To forbid; to prohibit or debar; as, to interdict
      intercourse with foreign nations.
      [1913 Webster]

            Charged not to touch the interdicted tree. --Milton.
      [1913 Webster]

   2. (Eccl.) To lay under an interdict; to cut off from the
      enjoyment of religious privileges, as a city, a church, an
      individual.
      [1913 Webster]

            An archbishop may not only excommunicate and
            interdict his suffragans, but his vicar general may
            do the same.                          --Ayliffe.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Interdict \In"ter*dict`\, n. [OE. entredit, enterdit, OF.
   entredit, F. interdit, fr. L. interdictum, fr. interdicere to
   interpose, prohibit; inter between + dicere to say. See
   Diction.]
   [1913 Webster]
   1. A prohibitory order or decree; a prohibition.
      [1913 Webster]

            These are not fruits forbidden; no interdict
            Defends the touching of these viands pure. --Milton.
      [1913 Webster]

   2. (R. C. Ch.) A prohibition of the pope, by which the clergy
      or laymen are restrained from performing, or from
      attending, divine service, or from administering the
      offices or enjoying the privileges of the church.
      [1913 Webster]

   3. (Scots Law) An order of the court of session, having the
      like purpose and effect with a writ of injunction out of
      chancery in England and America.
      [1913 Webster]

WordNet (r) 3.0 (2006):

interdict
    n 1: an ecclesiastical censure by the Roman Catholic Church
         withdrawing certain sacraments and Christian burial from a
         person or all persons in a particular district
    2: a court order prohibiting a party from doing a certain
       activity [syn: interdict, interdiction]
    v 1: destroy by firepower, such as an enemy's line of
         communication
    2: command against; "I forbid you to call me late at night";
       "Mother vetoed the trip to the chocolate store"; "Dad nixed
       our plans" [syn: forbid, prohibit, interdict,
       proscribe, veto, disallow, nix] [ant: allow,
       countenance, let, permit]

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "interdict":
   Eighteenth Amendment, Prohibition Party, Volstead Act, arrest,
   arrestation, ban, bar, bench warrant, capias, caveat, check,
   constraint, contraband, control, cooling, cooling down,
   cooling off, curb, curtailment, death warrant, debar, deceleration,
   denial, deny, disallow, disallowance, embargo, enjoin, exclude,
   exclude from, exclusion, fieri facias, forbid, forbiddance,
   forbidden fruit, forbidding, habere facias possessionem, hindrance,
   index, index expurgatorius, index librorum prohibitorum, inhibit,
   inhibition, injunction, interdiction, interdictum, law,
   legal restraint, mandamus, mandate, mandatory injunction, mittimus,
   monopoly, nisi prius, no-no, notice, notification, outlaw, precept,
   preclude, preclusion, prevent, prevention, process, prohibit,
   prohibition, prohibitory injunction, proscribe, proscription,
   protection, protectionism, protective tariff, rationing, refusal,
   refuse, rein, reject, rejection, repress, repression, restraint,
   restraint of trade, restrictive covenants, retardation,
   retrenchment, rule out, ruling out, say no to, search warrant,
   self-control, shut out, slowing down, statute, sumptuary laws,
   suppress, suppression, taboo, tariff wall, thought control,
   warrant, warrant of arrest, warrant of attorney, writ, zoning,
   zoning laws



Bouvier's Law Dictionary, Revised 6th Ed (1856):

INTERDICT, civil Among the Romans it was an ordinance of the praetor, which
forbade or enjoined the parties in a suit to do something particularly
specified, until it should be decided definitely who had the right in
relation to it. Like an injunction, the interdict was merely personal in its
effects and it had also another similarity to it, by being temporary or
perpetual. Dig. 43, 1, 1, 3, and 4. See Story, E Jur. 865; Halif. Civ. Law,
ch. 6 Vicat, Vocab. h. v.; Hein. Elem. Pand. Ps. 6, Sec. 285. Vide
Injunction.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

INTERDICT, OR INTERDICTION, eccles. law. An ecclesiastical censure, by which
divine services are prohibited either to particular persons or particular
places. These tyrannical edicts, issued by ecclesiastical powers, have never
been in force in the United States.