Certain
Certain adjective - Having been established and usually not subject to change.
Usage example: a certain percentage of the profits will go to charity
Firm is a synonym for certain in characteristic topic. In some cases you can use "Firm" instead an adjective "Certain", when it comes to topics like change, undoubtable.
Firm
Firm adjective - Not showing weakness or uncertainty.
Usage example: a friendly fellow with a ready smile and a firm handshake
Certain is a synonym for firm in characteristic topic. Sometimes you can use "Certain" instead an adjective "Firm", if it concerns topics such as change, established.
Mutual synonyms
Both words in one sentence
- He maintains firm discipline at Hogwarts and insists on certain behaviors from students.
Source: Neutral Good -
A good example of creator pedigree comes into play here - Fuhr previously sunk the ship of Cy and Skids in Boy Meets Boy, and has issued firm statments that certain members of the cast specifically Skids and Tybalt will never see the others again.
Source: Teasing Creator -
Faced with the opportunity to drain as much money as possible from one of the clients at the law firm he works at, he tore up a certain document and got that client off the hook.
Source: Literature / Magic Time
Cite this Source
Firm and Certain. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/certain/firm
Certain & Firm. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/certain/firm>.
Firm or Certain. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/certain/firm.
Google Ngram Viewer shows how "certain" and "firm" have occurred on timeline