overserious
adjective
over·se·ri·ous
| \ ˌō-vər-ˈsir-ē-əs
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Definition of overserious
: unduly or excessively serious
an overserious person had an overserious expression on her face The story sometimes edges toward soapy melodrama but saves itself from becoming overserious with cheeky humor … — PublishersWeekly.com
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