Inobservance :: Inobservance (a.) Want or neglect of observance.
Nonobservance :: Nonobservance (n.) Neglect or failure to observe or fulfill.
Observance :: Observance (n.) The act or practice of observing or noticing with attention; a heeding or keeping with care; performance; -- usually with a sense of strictness and fidelity; as, the observance of the Sabbath is general; the strict observance of duties..
Observance :: Observance (n.) An act, ceremony, or rite, as of worship or respect; especially, a customary act or service of attention; a form; a practice; a rite; a custom..