14
fishy(adjective, great, honest, informal, extraordinary)
14
indecisive(adjective, clear, open, weak, delicate)
14
obscure(adjective, rough, dark, uncertain, unreasonable)
14
unclear(adjective, clear, open, obscure, rough)
14
vague(adjective, clear, open, obscure, rough)
13
shady(adjective, open, honest, unusual, strange)
13
improbable(adjective, extraordinary, uncertain, fantastic, dubious)
13
in doubt(expression, adjective, idiom, clear, certain)
13
incredulous(adjective, indecisive, skeptical, unbelieving)
13
unlikely(adjective, slight, uncertain, shaky, dubious)
13
unreliable(adjective, delicate, uncertain, nervous, unstable)
12
borderline(adjective, clear, open, delicate, certain)
12
incredible(adjective, great, extraordinary, unreasonable, fantastic)
12
indistinct(adjective, obscure, rough, uncertain, dim)
11
in question(expression, adjective, idiom, clear, obscure)
11
chancy(noun, adjective, clear, delicate, certain)
11
disbelieving(adjective, person, uncertain, hesitant, suspicious)
11
implausible(adjective, extraordinary, fantastic, amazing, dubious)
11
indeterminate(adjective, clear, obscure, rough, certain)
11
mistrustful(adjective, uncertain, anxious, nervous, worried)
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APASmart Define. (2016). doubtful thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/doubtful/thesaurus/synonyms
ChicagoSmart Define. 2016. "doubtful thesaurus" https://smartdefine.org/doubtful/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, doubtful thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/doubtful/thesaurus/synonyms>.
MLASmart Define. "doubtful thesaurus" 24 March 2016. Web. 22 September 2026. <https://smartdefine.org/doubtful/thesaurus/synonyms>