The Collaborative International Dictionary of English v.0.48:

Decency \De"cen*cy\, n.; pl. Decencies. [L. decentia, fr.
   decens: cf. F. d['e]cence. See Decent.]
   1. The quality or state of being decent, suitable, or
      becoming, in words or behavior; propriety of form in
      social intercourse, in actions, or in discourse; proper
      formality; becoming ceremony; seemliness; hence, freedom
      from obscenity or indecorum; modesty.
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            Observances of time, place, and of decency in
            general.                              --Burke.
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            Immodest words admit of no defense,
            For want of decency is want of sense. --Roscommon.
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   2. That which is proper or becoming.
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            The external decencies of worship.    --Atterbury.
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            Those thousand decencies, that daily flow
            From all her words and actions.       --Milton.
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Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "decencies":
   amenities, appropriateness, civilities, civility, comity,
   convention, correctitude, correctness, courtliness, decency,
   decorousness, decorum, diplomatic code, elegance, elegancies,
   etiquette, exquisite manners, fitness, fittingness, formalities,
   good form, good manners, goodness, manners, mores,
   natural politeness, niceness, normality, normativeness,
   point of etiquette, politeness, politesse, properness, proprieties,
   propriety, protocol, punctilio, quiet good manners, righteousness,
   rightness, rules of conduct, seemliness, social code,
   social conduct, social graces, social procedures, social usage,
   suitability