IPA: /nɒnˈɒbvəns/
KK: /nɑnˈɑbvɚns/
The act of not following or respecting a rule, law, or custom, especially in a religious context.
The nonobservance of the holiday led to disappointment among the community members.
Nonobservance → It is formed from "non-" (meaning not) and "observance" (from Latin "observantia", meaning the act of observing or following). The word "nonobservance" refers to the act of not observing or failing to follow a rule or practice.
Think of 'not' ('non-') following or 'observing' something — that's why nonobservance means failing to observe a rule.