217 entries under essential topic. ×

4
needful(adjective, important, significant, original, capital)
4
nitty-gritty(noun, adjective, part, important)
4
postulate(noun, verb, law, support, regulation)
4
prerequisite(noun, adjective, important, need, significant)
4
root(noun, adjective, support, action, drop)
3
absolute(noun, adjective, rule, certain)
3
assumption(noun, law, support, regulation, action)
3
deep-seated(adjective, characteristic, original, fixed)
3
essence(noun, support, action, cause, start)
3
ingredient(noun, drop, part, material)
3
keystone(noun, law, support, regulation, action)
3
meat-and-potatoes(adjective, important, original, critical)
3
must(noun, condition, need, certainty)
3
part and parcel(noun, expression, adjective, idiom, characteristic)
3
particular(noun, drop, part, material)
3
quintessential(adjective, important, significant, basic)
3
required(adjective, important, significant, capital)
3
requirement(noun, concern, demand, need)
3
theoretical(adjective, important, original, basic)
3
underived(adjective, simple, rough, important, original)
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APASmart Define. (2016). fundamental thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/fundamental/thesaurus/synonyms
ChicagoSmart Define. 2016. "fundamental thesaurus" https://smartdefine.org/fundamental/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2016, fundamental thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/fundamental/thesaurus/synonyms>.
MLASmart Define. "fundamental thesaurus" 29 March 2016. Web. 26 September 2026. <https://smartdefine.org/fundamental/thesaurus/synonyms>