The Collaborative International Dictionary of English v.0.48:

Abrogation \Ab`ro*ga"tion\, n. [L. abrogatio, fr. abrogare: cf.
   F. abrogation.]
   The act of abrogating; repeal by authority.    --Hume.
   [1913 Webster]

WordNet (r) 3.0 (2006):

abrogation
    n 1: the act of abrogating; an official or legal cancellation
         [syn: abrogation, repeal, annulment]