18
rigid(adjective, strain, firmness, labour, hardness)
18
robust(adjective, strain, firmness, labour, hardiness)
18
substantial(adjective, strain, firmness, labour, hardiness)
18
unyielding(adjective, strain, firmness, labour, hardness)
17
conviction(noun, confidence, assurance, certainty, undoubtedness)
15
test(noun, study, check, cause, reason)
15
testimony(noun, information, mark, cause, knowledge)
14
certainty(noun, confidence, assurance, truth, undoubtedness)
14
conclusion
14
confirmation(noun, check, information, mark, sign)
14
veracity(noun, truth)
14
verification(noun, support, study, check, measure)
14
reasoning(noun, reason, case, claim, analysis)
14
truth(noun, truth)
14
validation(noun, display, true, approval, evidence)
13
attestation(noun, information, mark, sign, true)
13
axiom(noun, support, action, base, beginning)
13
consequence
13
knowledge(noun, action, understanding, information, experience)
13
reason(noun, support, action, cover, cause)
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APASmart Define. (2015). proof thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/proof/thesaurus/synonyms
ChicagoSmart Define. 2015. "proof thesaurus" https://smartdefine.org/proof/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, proof thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/proof/thesaurus/synonyms>.
MLASmart Define. "proof thesaurus" 22 December 2015. Web. 22 September 2026. <https://smartdefine.org/proof/thesaurus/synonyms>