The Collaborative International Dictionary of English v.0.48:

Indecency \In*de"cen*cy\, n.; pl. Indecencies. [L. indecentia
   unseemliness: cf. F. ind['e]cence.]
   [1913 Webster]
   1. The quality or state of being indecent; lack of decency,
      modesty, or good manners; obscenity.
      [1913 Webster]

   2. That which is indecent; an indecent word or act; an
      offense against delicacy.
      [1913 Webster]

            They who, by speech or writing, present to the ear
            or the eye of modesty any of the indecencies I
            allude to, are pests of society.      --Beattie.

   Syn: Indelicacy; indecorum; immodesty; impurity; obscenity.
        See Indecorum.
        [1913 Webster]

WordNet (r) 3.0 (2006):

indecency
    n 1: the quality of being indecent [ant: decency]
    2: an indecent or improper act [syn: indecency, impropriety]