157 entries under dubious topic. ×

2
odd(adjective, unusual, strange, irregular)
2
rare(weak, unlikely, implausible, improbable)
2
thick(adjective, great, extraordinary, amazing)
2
thin(adjective, weak, great, extraordinary, unreasonable)
2
ticklish(noun, adjective, weak, delicate, uncertain)
2
unconfirmed(adjective, uncertain, shaky, vague)
2
undefined(adjective, weak, dark, uncertain, dim)
2
unreasonable(adjective, unlikely, flimsy, unbelievable)
2
unsubstantial(extraordinary, unreasonable, amazing, unlikely)
1
betwixt and between(expression, idiom, open, uncertain)
1
cockamamie(extraordinary, amazing, astonishing, incredible)
1
cockeyed(extraordinary, amazing, astonishing, incredible)
1
faint(unsettled, unclear, hazy, indistinct)
1
fickle(adjective, weak, uncertain, sensitive, hesitant)
1
flaky(extraordinary, unusual, strange, amazing)
1
for the birds(expression, idiom, extraordinary, unreasonable)
1
full of holes(expression, idiom, extraordinary, unreasonable)
1
harebrained(extraordinary, amazing, astonishing, incredible)
1
incogitable(extraordinary, amazing, astonishing, incredible)
1
irregular(unusual, strange, vague, changeable)
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APASmart Define. (2016). doubtful thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/doubtful/thesaurus/synonyms
ChicagoSmart Define. 2016. "doubtful thesaurus" https://smartdefine.org/doubtful/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2016, doubtful thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/doubtful/thesaurus/synonyms>.
MLASmart Define. "doubtful thesaurus" 24 March 2016. Web. 26 September 2026. <https://smartdefine.org/doubtful/thesaurus/synonyms>