Inconceivable and Preposterous

Inconceivable

Inconceivable adjective - Too extraordinary or improbable to believe.
Usage example: the formerly inconceivable idea that humans could land on the moon

Preposterous is a synonym for inconceivable in illogical topic. In some cases you can use "Preposterous" instead an adjective "Inconceivable", when it comes to topics like impossible, unimaginable.

Nearby Word: inconceivability

Preposterous

Preposterous adjective - Conceived or made without regard for reason or reality.
Usage example: the idea that extraterrestrials built the pyramids is preposterous

Inconceivable is a synonym for preposterous in illogical topic. You can use "Inconceivable" instead an adjective "Preposterous", if it concerns topics such as unimaginable.
Cite this Source
Preposterous and Inconceivable. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/inconceivable/preposterous
Inconceivable & Preposterous. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/inconceivable/preposterous>.
Preposterous or Inconceivable. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/inconceivable/preposterous.
Google Ngram Viewer shows how "inconceivable" and "preposterous" have occurred on timeline