86 entries under big topic. ×

9
principal(adjective, good, great, important)
7
large(adjective, strong, important, substantial)
7
pressing(verb, adjective, tough, severe)
6
distinguished(adjective, extraordinary, superior, unusual)
6
exceptional(adjective, solid, extraordinary, superior)
6
marked(adjective, clear, solid, extraordinary, superior)
6
necessary(adjective, important, original, substantial)
6
primary(adjective, superior, unusual, important)
6
urgent(adjective, clear, tough, severe)
5
heavy(adjective, great, tough, severe)
5
valuable(adjective, good, important, substantial)
4
evident(adjective, clear, unusual, important)
4
sensible(adjective, good, substantial, definite)
3
extensive(adjective, substantial, large, valuable)
3
healthy(adjective, important, substantial, definite)
2
far-reaching(adjective, severe, important, substantial)
2
heavyweight(great, heavy, important, substantial)
2
imperative(adjective, important, determined, substantial)
2
importunate(adjective, great, important, substantial)
2
renowned(adjective, important, outstanding, substantial)
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APASmart Define. (2016). significant thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/significant/thesaurus/synonyms
ChicagoSmart Define. 2016. "significant thesaurus" https://smartdefine.org/significant/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, significant thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/significant/thesaurus/synonyms>.
MLASmart Define. "significant thesaurus" 4 March 2016. Web. 25 September 2026. <https://smartdefine.org/significant/thesaurus/synonyms>