107 entries under basic topic. ×

9
staple(adjective, lead, head, master, whole)
7
momentous(adjective, good, bad, great, excellent)
7
necessary(adjective, body, material, big, important)
7
radical(adjective, great, importance, important, significant)
6
crucial(adjective, great, big, important, significant)
5
elemental(adjective, body, material, important, significant)
5
underlying(adjective, important, significant, original, essential)
4
basal(adjective, body, lead, material, important)
4
overruling(adjective, importance, serious, essential)
4
rudimentary(adjective, important, significant, original, essential)
3
constitutional(adjective, body, material, important, significant)
3
indispensable(adjective, important, significant, original, serious)
3
original(adjective, order, body, material, heavy)
3
requisite(adjective, important, significant, original, capital)
2
compelling(adjective, important, significant, serious, essential)
2
deep(adjective, original, primary)
2
imperative(adjective, big, important, significant, substantial)
2
inherent(adjective, material, natural, essential)
2
integral(adjective, body, material, important, significant)
2
intrinsic(adjective, important, significant, original, essential)
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APASmart Define. (2016). principal thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/principal/thesaurus/synonyms
ChicagoSmart Define. 2016. "principal thesaurus" https://smartdefine.org/principal/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2016, principal thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/principal/thesaurus/synonyms>.
MLASmart Define. "principal thesaurus" 29 March 2016. Web. 20 September 2026. <https://smartdefine.org/principal/thesaurus/synonyms>