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