1) Annulment 2) Cancel 3) Canceling 4) Cancellation 5) Defeasance 6) French word used in English 7) Nullification 8) Recision 9) Repeal 10) Rescission 11) Revocation 12) Revokement 13) The act of abrogating 14) Vacatur 
• (n.) The act of abrogating; repeal by authority.
formally ending something you have agreed to legally (e.g. a treaty)
Ab`ro·ga'tion noun [ Latin abrogatio , from abrogare : confer French abrogation .] The act of abrogating; repeal by authority. Hume. 
The destruction or annulling of a former law, by an act of the legislative power, or by usage. A law may be abrogated or only derogated from; it is abrogated when it is totally annulled; it is derogated from when only a part is abrogated: derogatur legi, cum pars detrahitur; abrogatur legi, cum prorsus tollitur. Lex rogatur dum fertur; abrogatur du...
[n] - the act of abrogating
repeal noun the act of abrogating; an official or legal cancellation
an official or legal cancellation