94 entries under essential topic. ×

11
outstanding(adjective, bad, great, tough, top)
10
vital(adjective, body, great, importance, material)
9
elementary(adjective, important, significant, original)
9
significant(adjective, good, great, big, important)
8
number one(noun, expression, adjective, order, bad)
8
preeminent(adjective, order, bad, great, tough)
7
momentous(adjective, good, bad, great, excellent)
7
necessary(adjective, body, material, big, important)
7
radical(adjective, great, importance, important, significant)
6
controlling(adjective, top, superior, important, head)
6
crucial(adjective, great, big, important, significant)
5
elemental(adjective, body, material, important, significant)
5
underlying(adjective, important, significant, original)
4
basal(adjective, body, lead, material, important)
4
overruling(adjective, importance, serious, basic)
4
rudimentary(adjective, important, significant, original)
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)
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APASmart Define. (2016). principal thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/principal/thesaurus/synonyms
ChicagoSmart Define. 2016. "principal thesaurus" https://smartdefine.org/principal/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2016, principal thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/principal/thesaurus/synonyms>.
MLASmart Define. "principal thesaurus" 29 March 2016. Web. 26 September 2026. <https://smartdefine.org/principal/thesaurus/synonyms>