Source : Webster's Revised Unabridged Dictionary (1913)

Misfeasance \Mis*fea"sance\, n. [OF. pref. mes- wrong (L. minus
   less) + faisance doing, fr. faire to do, L. facere. Cf.
   {Malfeasance}.] (Law)
   A trespass; a wrong done; the improper doing of an act which
   a person might lawfully do. --Bouvier. Wharton.

Source : WordNet®

misfeasance
     n : doing a proper act in a wrongful or injurious manner