Source : Webster's Revised Unabridged Dictionary (1913)

Imprudence \Im*pru"dence\, n. [L. imprudentia: cf. F.
   imprudence. Cf. {Improvidence}.]
   The quality or state of being imprudent; want to caution,
   circumspection, or a due regard to consequences;
   indiscretion; inconsideration; reshness; also, an imprudent
   act; as, he was guilty of an imprudence.

         His serenity was interrupted, perhaps, by his own
         imprudence.                              --Mickle.

Source : WordNet®

imprudence
     n : a lack of caution in practical affairs [ant: {prudence}]