Doubtful and Improbable

Doubtful

Doubtful adjective - Giving good reason for being doubted, questioned, or challenged.
Usage example: the election results were highly doubtful, so an investigation was begun

Improbable is a synonym for doubtful in unlikely topic. In some cases you can use "Improbable" instead an adjective "Doubtful", when it comes to topics like likely. popular alternative

Improbable

Improbable adjective - Not likely to be true or to occur.
Usage example: it seems improbable that the two writers never met since they traveled in the same social circles

Doubtful is a synonym for improbable in unlikely topic. You can use "Doubtful" instead an adjective "Improbable", if it concerns topics such as likely, not likely. popular alternative

Nearby Words: improbability, improbably
Cite this Source
Improbable and Doubtful. (2016). Retrieved 2026, August 15, from https://thesaurus.plus/related/doubtful/improbable
Doubtful & Improbable. N.p., 2016. Web. 15 Aug. 2026. <https://thesaurus.plus/related/doubtful/improbable>.
Improbable or Doubtful. 2016. Accessed August 15, 2026. https://thesaurus.plus/related/doubtful/improbable.
Google Ngram Viewer shows how "doubtful" and "improbable" have occurred on timeline