The Collaborative International Dictionary of English v.0.48:

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; rashness; also, an imprudent
   act; as, he was guilty of an imprudence.
   [1913 Webster]

         His serenity was interrupted, perhaps, by his own
         imprudence.                              --Mickle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

imprudence
    n 1: a lack of caution in practical affairs [ant: prudence]