Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
nonobligatory is an adjective meaning "not required by rule or law". It carries one recorded sense.
not required by rule or law
Definitions, synonyms and semantic relations for nonobligatory come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.