The Collaborative International Dictionary of English v.0.48:

Dishonor \Dis*hon"or\ (d[i^]s*[o^]n"[~e]r or
   d[i^]z*[o^]n"[~e]r), v. t. [imp. & p. p. Dishonored
   (d[i^]s*[o^]n"[~e]rd or d[i^]z*[o^]n"[~e]rd); p. pr. & vb. n.
   Dishonoring.] [OE. deshonouren, F. d['e]shonorer; pref.
   d['e]s- (L. dis-) + honorer to honor, fr. L. honorare. See
   Honor, v. t.] [Written also dishonour.]
   1. To deprive of honor; to disgrace; to bring reproach or
      shame on; to treat with indignity, or as unworthy in the
      sight of others; to stain the character of; to lessen the
      reputation of; as, the duelist dishonors himself to
      maintain his honor.
      [1913 Webster]

            Nothing . . . that may dishonor
            Our law, or stain my vow of Nazarite. --Milton.
      [1913 Webster]

   2. To violate the chastity of; to debauch. --Dryden.
      [1913 Webster]

   3. To refuse or decline to accept or pay; -- said of a bill,
      check, note, or draft which is due or presented; as, to
      dishonor a bill exchange.

   Syn: To disgrace; shame; debase; degrade; lower; humble;
        humiliate; debauch; pollute.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dishonor \Dis*hon"or\ (d[i^]s*[o^]n"[~e]r or
   d[i^]z*[o^]n"[~e]r), n. [OE. deshonour, dishonour, OF.
   deshonor, deshonur, F. d['e]shonneur; pref. des- (L. dis-) +
   honor, honur, F. honneur, fr. L. honor. See Honor.]
   [Written also dishonour.]
   [1913 Webster]
   1. Lack of honor; disgrace; ignominy; shame; reproach.
      [1913 Webster]

            It was not meet for us to see the king's dishonor.
                                                  --Ezra iv. 14.
      [1913 Webster]

            His honor rooted in dishonor stood.   --Tennyson.
      [1913 Webster]

   2. (Law) The nonpayment or nonacceptance of commercial paper
      by the party on whom it is drawn.

   Syn: Disgrace; ignominy; shame; censure; reproach;
        opprobrium.
        [1913 Webster]

WordNet (r) 3.0 (2006):

dishonor
    n 1: a state of shame or disgrace; "he was resigned to a life of
         dishonor" [syn: dishonor, dishonour] [ant: honor,
         honour, laurels]
    2: lacking honor or integrity [syn: dishonor, dishonour]
       [ant: honor, honour]
    v 1: bring shame or dishonor upon; "he dishonored his family by
         committing a serious crime" [syn: dishonor, disgrace,
         dishonour, attaint, shame] [ant: honor, honour,
         reward]
    2: force (someone) to have sex against their will; "The woman
       was raped on her way home at night" [syn: rape, ravish,
       violate, assault, dishonor, dishonour, outrage]
    3: refuse to accept; "dishonor checks and drafts" [syn:
       dishonor, dishonour] [ant: honor, honour]

Moby Thesaurus II by Grady Ward, 1.0:

145 Moby Thesaurus words for "dishonor":
   abase, abuse, affront, aspersion, bad character, bad debt,
   bad name, bad odor, bad report, bad reputation, bad repute,
   belittlement, black mark, blemish, blot, bring into discredit,
   bring low, bring shame upon, call names, cast reproach upon,
   commit sacrilege, corruptedness, corruption, corruptness,
   criminality, crookedness, debase, debauch, defamation, default,
   defection, defile, deflower, defrock, degrade, delinquence,
   delinquency, denigration, deplume, depreciation, derogation,
   desecrate, detraction, deviousness, disallow, disapprobation,
   discourtesy, discredit, disesteem, disfavor, disgrace, dishonesty,
   dishonoring, disoblige, disparagement, displume, disrepute,
   disrespect, disrespectfulness, dump on, evasiveness, evil repute,
   feloniousness, fleer at, flout, fraudulence, fraudulency, gibe at,
   give offense to, humble, humiliate, hurl a brickbat, ignominy,
   ill fame, ill repute, ill-favor, improbity, impudence,
   impute shame to, indignity, indirection, infamy, injure, insolence,
   insult, irreverence, jeer at, jibe at, lack of respect, levant,
   libel, mock, mortify, nondischarge of debts, nonpayment,
   nonremittal, not pay, obloquy, odium, offend, opprobrium, outrage,
   pillory, poor reputation, profane, protest, protested bill,
   public dishonor, put down, put to shame, rape, ravish,
   reflect discredit upon, refuse to pay, reproach, repudiate,
   repudiation, ridicule, scoff at, seduce, shadiness,
   shady reputation, shame, shiftiness, slander, slight, slipperiness,
   slur, smear, smirch, stop payment, taunt, treat with indignity,
   trickiness, uncollectible, unconscientiousness, underhandedness,
   unfrock, unsavoriness, unsavory reputation, unscrupulousness,
   unstraightforwardness, violate, vitiate, welsh