22
unbeliever(noun, person, belief, detractor, nonconformist)
13
doubter(noun, person, belief, detractor, unbelief doubt)
12
agnostic(noun, person, irreligion, unbelieving, doubter)
10
cynic(noun, person, incredulity, unbelief doubt, unbelieving)
10
disbeliever(noun, person, unbelieving, doubter, unbeliever)
9
dissenter(noun, person, dissident, unbelieving, doubter)
9
freethinker(noun, person, radical, nonconformist, irreligion)
9
infidel(noun, adjective, person, irreligion, unbelieving)
8
heathen(noun, adjective, person, not, irreligion)
7
atheist(noun, person, irreligion, unbelieving, unbeliever)
7
heretic(noun, person, incredulity, unbelieving, doubter)
7
questioner(noun, person, detractor, cynic, unbelieving)
6
doubting thomas(noun, person, belief, detractor, unbelieving)
4
sceptic
4
latitudinarian(irreligion, doubter)
4
nonbeliever(noun, adjective, person, belief, detractor)
4
pessimist(noun, person, unbelieving, unbeliever)
4
pyrrhonist(incredulity, irreligion)
4
sceptical
4
skeptical
11 years ago|5.6k views|share |citing 
APASmart Define. (2015). skeptic thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/skeptic/thesaurus/synonyms
ChicagoSmart Define. 2015. "skeptic thesaurus" https://smartdefine.org/skeptic/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, skeptic thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/skeptic/thesaurus/synonyms>.
MLASmart Define. "skeptic thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/skeptic/thesaurus/synonyms>