Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
unobservant is an adjective meaning "not consciously observing". It carries one recorded sense.
not consciously observing
“looked through him with blank unseeing eyes”
Definitions, synonyms and semantic relations for unobservant come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.