The Collaborative International Dictionary of English v.0.48:

Dignity \Dig"ni*ty\, n.; pl. Dignities. [OE. dignete, dignite,
   OF. dignet['e], dignit['e], F. dignit['e], fr. L. dignitas,
   from dignus worthy. See Dainty, Deign.]
   1. The state of being worthy or honorable; elevation of mind
      or character; true worth; excellence.
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   2. Elevation; grandeur.
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            The dignity of this act was worth the audience of
            kings.                                --Shak.
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   3. Elevated rank; honorable station; high office, political
      or ecclesiastical; degree of excellence; preferment;
      exaltation. --Macaulay.
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            And the king said, What honor and dignity hath been
            done to Mordecai for this?            --Esth. vi. 3.
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            Reuben, thou art my firstborn, . . . the excellency
            of dignity, and the excellency of power. --Gen.
                                                  xlix. 3.
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   4. Quality suited to inspire respect or reverence; loftiness
      and grace; impressiveness; stateliness; -- said of mien,
      manner, style, etc.
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            A letter written with singular energy and dignity of
            thought and language.                 --Macaulay.
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   5. One holding high rank; a dignitary.
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            These filthy dreamers . . . speak evil of dignities.
                                                  --Jude. 8.
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   6. Fundamental principle; axiom; maxim. [Obs.]
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            Sciences concluding from dignities, and principles
            known by themselves.                  --Sir T.
                                                  Browne.

   Syn: See Decorum.
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   To stand upon one's dignity, to have or to affect a high
      notion of one's own rank, privilege, or character.
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            They did not stand upon their dignity, nor give
            their minds to being or to seeming as elegant and as
            fine as anybody else.                 --R. G. White.
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WordNet (r) 3.0 (2006):

dignity
    n 1: the quality of being worthy of esteem or respect; "it was
         beneath his dignity to cheat"; "showed his true dignity
         when under pressure" [syn: dignity, self-respect,
         self-regard, self-worth]
    2: formality in bearing and appearance; "he behaved with great
       dignity" [syn: dignity, lordliness, gravitas]
    3: high office or rank or station; "he respected the dignity of
       the emissaries"