8
critical(adjective, big, important, significant, substantial)
8
desirable(wanted, needed)
8
inexorable(adjective, certain, cruel, obvious, pitiless)
7
prime(adjective, body, material, important, significant)
7
assured(adjective, certain, regular, expected, inexorable)
7
incumbent(adjective, obligatory)
6
de rigueur(expression, adjective, right, essential, required)
6
decisive(adjective, important, substantial, valuable, essential)
6
demanded
6
fated(adjective, certain, obvious, expected, inexorable)
6
infallible(adjective, certain, inevitable)
6
momentous(adjective, important, substantial, valuable, essential)
6
paramount(adjective, important, significant, original, substantial)
6
staple
6
sure(certain, definite, obvious, expected, unquestionable)
5
central(adjective, important, significant, original, essential)
5
conclusive(adjective, demonstration, decisive, required, obligatory)
5
constraining(adjective, required, obligatory)
5
demand(noun, want, need, essential, certainty)
5
desideratum(noun, want, need, essential, certainty)
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APASmart Define. (2015). necessary thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/necessary/thesaurus/synonyms
ChicagoSmart Define. 2015. "necessary thesaurus" https://smartdefine.org/necessary/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, necessary thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/necessary/thesaurus/synonyms>.
MLASmart Define. "necessary thesaurus" 2 November 2015. Web. 22 September 2026. <https://smartdefine.org/necessary/thesaurus/synonyms>