nul·li·fi·ca·tion /ˌnə-lə-fə-'kā-shən/ n: the act of nullifying: the state of being nullified see also jury nullification

Merriam-Webster’s Dictionary of Law. . 1996.

n. The act or condition of negating the existence of a law, performed by individuals acting in a public capacity (for example, a jury) or by one level of government opposing the laws of another.
@ jury nullification
A jury's verdict of "not guilty" despite overwhelming evidence of guilt, often in the face of the jury's collective belief of this guilt, because of its perception that the law is being immorally or improperly applied to the defendant; in other words, the jury nullifies the law because it believes the defendant has been unfairly treated.

Webster's New World Law Dictionary. . 2000.