40 entries under essential topic. ×

24
mandatory(adjective, set, significant, affected)
23
obligatory(adjective, sound, important, certain, true)
20
necessary(adjective, cruel, pitiless, obligation)
19
required(adjective, significant, basic, vital)
16
requisite(adjective, significant, basic, vital)
13
indispensable(adjective, set, important, significant)
13
imperative(adjective, set, important, significant)
8
binding(adjective, sound, certain, true, significant)
7
compelling(adjective, violent, significant, basic)
5
vital(adjective, set, important, significant)
5
pressing(adjective, important, significant, critical)
5
unavoidable(adjective, certain, significant, near)
4
exigent(adjective, important, significant, critical)
4
needed(adjective, set, significant, basic)
4
urgent(adjective, important, significant, critical)
3
basic(adjective, significant, vital, fundamental)
3
crucial(adjective, important, significant, critical)
3
de rigueur(expression, adjective, idiom, significant)
3
needful(adjective, set, significant, basic)
3
prerequisite(adjective, set, significant, basic)
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APASmart Define. (2015). compulsory thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/compulsory/thesaurus/synonyms
ChicagoSmart Define. 2015. "compulsory thesaurus" https://smartdefine.org/compulsory/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, compulsory thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/compulsory/thesaurus/synonyms>.
MLASmart Define. "compulsory thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/compulsory/thesaurus/synonyms>