Certain
Certain adjective - Having been established and usually not subject to change.
Usage example: a certain percentage of the profits will go to charity
Fluctuating is an antonym for certain.
Fluctuating
Fluctuating adjective - Likely to change frequently, suddenly, or unexpectedly.
Usage example: a fluctuating stock market makes it hard for investors to know what to do
Certain is an antonym for fluctuating.
Both words in one sentence
- Item prices used to be set to a certain percent above or below the average price, with the average fluctuating depending on buying rates.
Source: Player-Generated Economy
Cite this Source
Fluctuating and Certain. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/certain/fluctuating
Certain & Fluctuating. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/certain/fluctuating>.
Fluctuating or Certain. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/certain/fluctuating.
Google Ngram Viewer shows how "certain" and "fluctuating" have occurred on timeline