200 entries under adjective topic. ×

2
big(great, significant, substantial, large)
2
bottom(important, significant, original, essential)
2
capital(important, serious, essential, critical)
2
in demand(expression, idiom, basic, main)
2
incumbent on(expression, essential, required, obligatory)
2
irrevocable(expected, predictable, inexorable, required)
2
life-or-death(important, essential, critical, basic)
2
material(big, significant, substantial, valuable)
2
prescribed(expected, predictable, inexorable, obligatory)
2
reasonable(sound, sensible, rational, probable)
2
relevant(clear, sound, reasonable, sensible)
2
specified(essential, required, needed)
2
suitable(wanted, obligatory, needed, compulsory)
2
unescapable(certain, obvious, inevitable, inescapable)
1
axiological(important, significant, original, essential)
1
constitutional(body, material, important, significant)
1
first(important, significant, original, essential)
1
fitting
1
foremost(important, significant, capital, essential)
1
foundational(important, significant, original, essential)
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APASmart Define. (2015). necessary thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/necessary/thesaurus/synonyms
ChicagoSmart Define. 2015. "necessary thesaurus" https://smartdefine.org/necessary/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, necessary thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/necessary/thesaurus/synonyms>.
MLASmart Define. "necessary thesaurus" 2 November 2015. Web. 25 September 2026. <https://smartdefine.org/necessary/thesaurus/synonyms>