59 entries under serious topic. ×

33
significant(adjective, good, clear, strong, show)
18
important(adjective, good, strong, great, tough)
18
weighty(adjective, good, clear, strong, great)
12
grave(adjective, dull, quiet, great, tough)
9
earnest(adjective, dull, quiet, severe, importance)
7
notable(adjective, great, importance, unusual, important)
7
outstanding(adjective, great, importance, unusual, important)
7
solemn(adjective, dull, quiet, severe, importance)
6
deep(adjective, tough, severe, sad, important)
4
heavy(adjective, dull, quiet, tough, severe)
4
sober(adjective, dull, quiet, severe, big)
3
crucial(great, severe, important, significant, substantial)
3
major(adjective, great, tough, severe, important)
2
cardinal(important, substantial, essential, critical)
2
close(adjective, severe, thoughtful, sober)
2
critical(great, important, significant, substantial)
2
major-league(adjective, strong, great, extraordinary, unusual)
2
urgent(severe, important, substantial, valuable)
1
firm(adjective, strong, severe, solid, important)
1
constant(adjective, thoughtful, sober, sincere)
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APASmart Define. (2016). meaningful thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/meaningful/thesaurus/synonyms
ChicagoSmart Define. 2016. "meaningful thesaurus" https://smartdefine.org/meaningful/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2016, meaningful thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/meaningful/thesaurus/synonyms>.
MLASmart Define. "meaningful thesaurus" 29 March 2016. Web. 29 September 2026. <https://smartdefine.org/meaningful/thesaurus/synonyms>