3
fine print(noun, expression, condition, essential, requirement)
3
necessary(noun, need, essential, obligation, requirement)
3
obligation(noun, condition, need, essential, requirement)
3
rule(noun, law, condition, essential, foundation)
3
small print(noun, expression, condition, essential, requirement)
2
arrangement(noun, condition, essential, requirement, qualification)
2
basic(noun, law, condition, heart, essential)
2
clause(condition, requirement, proviso)
2
contingency(noun, condition, essential, requirement, qualification)
2
crux(noun, heart, essential, essence, basic)
2
essence(noun, condition, need, essential, certainty)
2
essential condition
2
exception(noun, condition, essential, requirement, qualification)
2
exemption(noun, condition, essential, requirement, qualification)
2
heart(law, condition, essential, foundation, basic)
2
indispensable
2
keystone
2
kicker(noun, condition)
2
main point(noun, expression, essence, core, outcome)
2
main thing(noun, expression, essence, core, outcome)
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APASmart Define. (2015). sine qua non thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/sine_qua_non/thesaurus/synonyms
ChicagoSmart Define. 2015. "sine qua non thesaurus" https://smartdefine.org/sine_qua_non/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2015, sine qua non thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/sine_qua_non/thesaurus/synonyms>.
MLASmart Define. "sine qua non thesaurus" 10 April 2015. Web. 29 September 2026. <https://smartdefine.org/sine_qua_non/thesaurus/synonyms>