SERIOUS Synonyms: 184 Similar and Opposite Words - Merriam-Webster
https://www.merriam-webster.com/thesaurus/serious
WebSynonyms for SERIOUS: solemn, severe, earnest, stern, professional, sober, harsh, humorless; Antonyms of SERIOUS: humorous, joking, playful, flippant, jocular, facetious, funny, ridiculous
DA: 16 PA: 87 MOZ Rank: 69