55 entries under obligatory topic. ×

3
basic(adjective, important, significant, essential, critical)
3
compelling(adjective, important, significant, serious, essential)
3
fundamental(adjective, important, significant, capital, essential)
3
imperious(adjective, commanding, authoritative, domineering)
2
bounden(necessary, conclusive)
2
cardinal(adjective, important, significant, capital, essential)
2
chief(adjective, important, significant, serious, capital)
2
compulsatory(adjective, commanding, authoritative, domineering)
2
conclusive
2
constraining
2
decisive(adjective, important, significant, essential, critical)
2
enforced(verb, adjective, compulsory, mandatory)
2
exigent(adjective, important, significant, serious, essential)
2
irrevocable(necessary, conclusive)
2
principal(adjective, important, significant, serious, capital)
2
unavoidable(adjective, certain, significant, essential, sure)
1
bottom-line(adjective, important, significant, essential, critical)
1
elementary(adjective, significant, essential, basic, vital)
1
expedient(adjective, significant, essential, basic, vital)
1
incumbent on(expression, adjective, significant, essential, basic)
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APASmart Define. (2015). required thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/required/thesaurus/synonyms
ChicagoSmart Define. 2015. "required thesaurus" https://smartdefine.org/required/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, required thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/required/thesaurus/synonyms>.
MLASmart Define. "required thesaurus" 3 November 2015. Web. 26 September 2026. <https://smartdefine.org/required/thesaurus/synonyms>