The Collaborative International Dictionary of English v.0.48:

Breach \Breach\ (br[=e]ch), n. [OE. breke, breche, AS. brice,
   gebrice, gebrece (in comp.), fr. brecan to break; akin to
   Dan. br[ae]k, MHG. breche, gap, breach. See Break, and cf.
   Brake (the instrument), Brack a break] .
   1. The act of breaking, in a figurative sense.
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   2. Specifically: A breaking or infraction of a law, or of any
      obligation or tie; violation; non-fulfillment; as, a
      breach of contract; a breach of promise.
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   3. A gap or opening made made by breaking or battering, as in
      a wall or fortification; the space between the parts of a
      solid body rent by violence; a break; a rupture.
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            Once more unto the breach, dear friends, once more;
            Or close the wall up with our English dead. --Shak.
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   4. A breaking of waters, as over a vessel; the waters
      themselves; surge; surf.
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            The Lord hath broken forth upon mine enemies before
            me, as the breach of waters.          --2 Sam. v.
                                                  20.
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   A clear breach implies that the waves roll over the vessel
      without breaking.

   A clean breach implies that everything on deck is swept
      away. --Ham. Nav. Encyc.
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   5. A breaking up of amicable relations; rupture.
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            There's fallen between him and my lord
            An unkind breach.                     --Shak.
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   6. A bruise; a wound.
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            Breach for breach, eye for eye.       --Lev. xxiv.
                                                  20.
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   7. (Med.) A hernia; a rupture.
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   8. A breaking out upon; an assault.
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            The Lord had made a breach upon Uzza. --1. Chron.
                                                  xiii. 11.
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   Breach of falth, a breaking, or a failure to keep, an
      expressed or implied promise; a betrayal of confidence or
      trust.

   Breach of peace, disorderly conduct, disturbing the public
      peace.

   Breach of privilege, an act or default in violation of the
      privilege or either house of Parliament, of Congress, or
      of a State legislature, as, for instance, by false
      swearing before a committee. --Mozley. Abbott.
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   Breach of promise, violation of one's plighted word, esp.
      of a promise to marry.

   Breach of trust, violation of one's duty or faith in a
      matter entrusted to one.
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   Syn: Rent; cleft; chasm; rift; aperture; gap; break;
        disruption; fracture; rupture; infraction; infringement;
        violation; quarrel; dispute; contention; difference;
        misunderstanding.
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WordNet (r) 3.0 (2006):

breach of promise
    n 1: failure to keep a promise (of marriage)

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "breach of promise":
   Punic faith, bad faith, barratry, breach, breach of contract,
   breach of faith, breach of privilege, breach of trust, breaking,
   contravention, dereliction, disaffection, disloyalty,
   faithlessness, falseness, falsity, fickleness, inconstancy,
   infidelity, infraction, infringement, mala fides, offense,
   recreancy, transgression, trespass, trothlessness, unfaith,
   unfaithfulness, unloyalty, unsteadfastness, untrueness,
   violation