Seriousness
来自Big Physics
Safin(讨论 | 贡献)2022年4月27日 (三) 10:48的版本 (建立内容为“Category:etymology == google == [https://www.google.com.hk/search?q=seriousness+etymology&newwindow=1&hl=en ref] late Middle English: from Old French serieux…”的新页面)
late Middle English: from Old French serieux or late Latin seriosus, from Latin serius ‘earnest, serious’.
wiktionary
serious + -ness
etymonline
seriousness (n.)
1520s, from serious + -ness.