Certain and Nonrational

Opposite meaning words

Certain adjective - Known but not named.

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Nonrational is an antonym for certain.

Nearby Words: certainty, certainly

Nonrational adjective - Not using or following good reasoning.

Usage example: was so upset that he was completely nonrational for a moment

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Certain is an antonym for nonrational.

Cite this Source

Nonrational and Certain. (2016). Retrieved 2026, August 14, from https://thesaurus.plus/related/certain/nonrational

Certain & Nonrational. N.p., 2016. Web. 14 Aug. 2026. <https://thesaurus.plus/related/certain/nonrational>.

Nonrational or Certain. 2016. Accessed August 14, 2026. https://thesaurus.plus/related/certain/nonrational.

Google Ngram Viewer shows how "certain" and "nonrational" have occurred on timeline