The Collaborative International Dictionary of English v.0.48:
Nonobservance \Non`ob*serv"ance\ (n[o^]n`[o^]b*z[~e]rv"ans), n. Neglect or failure to observe or fulfill. [1913 Webster]WordNet (r) 3.0 (2006):
nonobservance n 1: a lack of conformity with law or custom or practice etc. [ant: honoring, observance]