13
basic(noun, adjective, body, material, important)
12
inescapable(adjective, cruel, pitiless, unrelenting, inexorable)
12
key(adjective, important, significant, original, essential)
11
binding(adjective, sound, essential, inexorable, required)
11
cardinal(noun, adjective, important, significant, original)
11
certain(adjective, regular, definite, obvious, expected)
11
compelling(adjective, reasonable, sensible, important, serious)
11
exigent(adjective, important, substantial, serious, valuable)
11
ineluctable(adjective, cruel, pitiless, unrelenting, inexorable)
10
involuntary(adjective, required, inevitable)
10
main(adjective, important, significant, original, capital)
10
must(noun, adjective, right, want, need)
10
need(noun, verb, want, essential, certainty)
10
pressing(adjective, important, substantial, serious, essential)
10
principal(adjective, body, material, big, important)
10
requirement(noun, want, need, essential, certainty)
10
significant(adjective, big, important, original, substantial)
10
undeniable(adjective, certain, definite, expected, unquestionable)
10
wanted(adjective, important, capital, essential, vital)
8
chief(adjective, big, important, significant, substantial)
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APASmart Define. (2015). necessary thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/necessary/thesaurus/synonyms
ChicagoSmart Define. 2015. "necessary thesaurus" https://smartdefine.org/necessary/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, necessary thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/necessary/thesaurus/synonyms>.
MLASmart Define. "necessary thesaurus" 2 November 2015. Web. 20 September 2026. <https://smartdefine.org/necessary/thesaurus/synonyms>