4
affirm(verb, support, maintain, secure, back)
4
endorse(verb, support, take, check, maintain)
3
accept
3
approve(verb, support, take, favor, agree)
3
assure(verb, support, maintain, secure, back)
3
certify(verb, support, maintain, secure, back)
3
confirm(verb, support, maintain, secure, back)
3
countersign(verb, sign, rubber-stamp, undersign)
3
support(noun, verb, take, maintain, secure)
3
underwrite(verb, support, take, agree, sign)
3
warrant(verb, support, maintain, secure, back)
2
answer for(verb, expression, phrasal verb, support, maintain)
2
authenticate(verb, sign)
2
back(verb, adverb, support, take, maintain)
2
co-sign
2
get behind(verb, expression, phrasal verb, support, take)
2
guarantee(verb, support, maintain, back, declare)
2
notarize(verb, sign, underwrite, subscribe, authenticate)
2
prove(verb, support, maintain, secure, back)
2
sanction(verb, support, take, favor, agree)
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APASmart Define. (2015). cosign thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/cosign/thesaurus/synonyms
ChicagoSmart Define. 2015. "cosign thesaurus" https://smartdefine.org/cosign/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, cosign thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/cosign/thesaurus/synonyms>.
MLASmart Define. "cosign thesaurus" 24 December 2015. Web. 21 September 2026. <https://smartdefine.org/cosign/thesaurus/synonyms>