Serious
Serious adjective - Not joking or playful in mood or manner.
Unflappable and serious are semantically related. In some cases you can use "Unflappable" instead an adjective "Serious".
Nearby Words: seriously, seriousness
Unflappable
Unflappable adjective - Not easily panicked or upset.
Serious and unflappable are semantically related. Sometimes you can use "Serious" instead an adjective "Unflappable".
Both words in one sentence
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Is Serious Business: Nick is normally calm and unflappable.
Source: Disney / Zootopia -
Is Serious Business: Only In Death has various examples, such as straitlaced Daur almost hitting Rawne, unflappable Mkoll getting spooked and chatty Maggs being quiet.
Source: Literature / Gaunt's Ghosts -
Is Serious Business: The normally unflappable Lillian blows up at Kris, Richard and Ramona's older sister, after she overhears what sounds like Kris making a rather lewd proposition to Roomie.
Source: Webcomic / Go Get a Roomie!
Cite this Source
Unflappable and Serious. (2016). Retrieved 2026, August 01, from https://thesaurus.plus/related/serious/unflappable
Serious & Unflappable. N.p., 2016. Web. 01 Aug. 2026. <https://thesaurus.plus/related/serious/unflappable>.
Unflappable or Serious. 2016. Accessed August 01, 2026. https://thesaurus.plus/related/serious/unflappable.
Google Ngram Viewer shows how "serious" and "unflappable" have occurred on timeline