2
reasonable(adjective, sound, sensible, rational, probable)
2
relevant(adjective, clear, sound, reasonable, sensible)
2
specified(adjective, essential, required, needed)
2
suitable(adjective, wanted, obligatory, needed, compulsory)
2
true(sound, certain, definite, unquestionable, indisputable)
2
unescapable(adjective, certain, obvious, inevitable, inescapable)
2
unpreventable(expected, predictable, inexorable, undeniable, unavoidable)
2
unstoppable
2
weighty(big, important, significant, substantial, valuable)
1
amoebic(material, natural, basic, living, functional)
1
analytic(clear, sound, reasonable, sensible, rational)
1
analytical(clear, sound, reasonable, sensible, rational)
1
anatomical(material, natural, basic, living, functional)
1
animate(material, natural, basic, living, functional)
1
axiological(adjective, important, significant, original, essential)
1
axiomatic(important, significant, original, basic, vital)
1
basement
1
big-league(significant, vital, imperative)
1
biological(material, natural, basic, living, functional)
1
biotic(material, natural, basic, living, functional)
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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>