142 entries under substantial topic. ×

2
super(adjective, good, extraordinary, big, unusual)
1
actual
1
ad rem(expression, important, serious, related)
1
clear-cut(sharp, definite, considerable, cutting)
1
definite(adjective, superior, energetic, big, unusual)
1
determining(big, important, serious, valuable)
1
doozie(big, important, outstanding, large)
1
dynamite(big, important, large)
1
exigent(adjective, great, big, heavy, important)
1
fab(big, important, large)
1
fat(adjective, big, heavy, important)
1
front-page(big, important, valuable, vital)
1
hefty(adjective, big, heavy, large)
1
immanent
1
interesting(adjective, outstanding, notable, profound)
1
intrinsic(adjective, important, original, serious)
1
manifest(adjective, clear, unusual, important, famous)
1
massive(big, heavy, large, considerable)
1
mattering much(expression, big, valuable, vital)
1
mondo(big, important, large)
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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>