renunciation

(noun) rejecting or disowning or disclaiming as invalid. Synonyms: repudiation. Example: "Congressional repudiation of the treaty that the president had negotiated."

(noun) the state of having rejected your religious beliefs or your political party or a cause (often in favor of opposing beliefs or causes). Synonyms: apostasy, defection.

(noun) an act (spoken or written) declaring that something is surrendered or disowned. Synonyms: renouncement.

(noun) the act of renouncing; sacrificing or giving up or surrendering (a possession or right or title or privilege etc.). Synonyms: forgoing, forswearing.