The Collaborative International Dictionary of English v.0.48:

Impunity \Im*pu"ni*ty\, n. [L. impunitas, fr. impunis without
   punishment; pref. im- not + poena punishment: cf. F.
   impunit['e]. See Pain.]
   Exemption or freedom from punishment, harm, or loss.
   [1913 Webster]

         Heaven, though slow to wrath,
         Is never with impunity defied.           --Cowper.
   [1913 Webster]

         The impunity and also the recompense.    --Holland.
   [1913 Webster]

WordNet (r) 3.0 (2006):

impunity
    n 1: exemption from punishment or loss

The Devil's Dictionary (1881-1906):

IMPUNITY, n.  Wealth.