Certain and Undecided

Opposite meaning words

Certain adjective - Impossible to avoid or evade.

Usage example: as he got older, the athlete began to feel the certain effects of the aging process on his body

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Undecided is an antonym for certain in topics: sure, fixed, confident, undoubtable, referring to a specifically known amount.

Nearby Words: certainty, certainly

Undecided adjective - Not yet settled or decided.

Usage example: a number of undecided matters still before the committee

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Certain is an antonym for undecided in not sure topic.

Nearby Word: undecidedly

Cite this Source

Undecided and Certain. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/certain/undecided

Certain & Undecided. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/certain/undecided>.

Undecided or Certain. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/certain/undecided.

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