The Collaborative International Dictionary of English v.0.48:

Indiscretion \In`dis*cre"tion\, n. [Pref. in- not + discretion:
   cf. F. indiscr['e]tion.]
   [1913 Webster]
   1. The quality or state of being indiscreet; lack of
      discretion; imprudence.
      [1913 Webster]

   2. An indiscreet act; indiscreet behavior.
      [1913 Webster]

            Past indiscretion is a venial crime.  --Cowper.
      [1913 Webster]

WordNet (r) 3.0 (2006):

indiscretion
    n 1: the trait of being injudicious [syn: indiscretion,
         injudiciousness]
    2: a petty misdeed [syn: indiscretion, peccadillo]

The Devil's Dictionary (1881-1906):

INDISCRETION, n.  The guilt of woman.