147 entries under fundamental topic. ×

5
bottom(noun, adjective, important, significant, original)
5
doctrine(noun, rule, opinion, principle)
5
necessity(noun, condition, want, heart, essential)
5
root(noun, adjective, drop, part, material)
4
imperative(noun, adjective, important, significant, essential)
3
absolute(adjective, essential, key, supreme)
3
needful(adjective, significant, original, essential, vital)
3
prerequisite(noun, adjective, important, want, significant)
3
required(adjective, important, significant, essential, critical)
3
significant(adjective, important, original, essential, critical)
3
structural(adjective, material, important, natural, original)
2
best(adjective, essential, supreme)
2
built-in(adjective, characteristic, natural, essential)
2
compulsory(adjective, significant, essential, vital)
2
decisive(adjective, important, significant, essential, critical)
2
embryonic(simple, beginning, opening, original)
2
heart(noun, law, part, condition, emotion)
2
life-or-death(important, essential, critical, key)
2
material(drop, part, element, essential, section)
2
needed(adjective, important, significant, essential, critical)
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APASmart Define. (2015). basic thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/basic/thesaurus/synonyms
ChicagoSmart Define. 2015. "basic thesaurus" https://smartdefine.org/basic/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, basic thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/basic/thesaurus/synonyms>.
MLASmart Define. "basic thesaurus" 10 April 2015. Web. 22 September 2026. <https://smartdefine.org/basic/thesaurus/synonyms>