Firm up
Firm up verb - To become physically firm or solid.
Make firm
Mutual synonyms
Cite this Source
Make firm and Firm up. (2016). Retrieved 2026, August 14, from https://thesaurus.plus/related/firm_up/make_firm
Firm up & Make firm. N.p., 2016. Web. 14 Aug. 2026. <https://thesaurus.plus/related/firm_up/make_firm>.
Make firm or Firm up. 2016. Accessed August 14, 2026. https://thesaurus.plus/related/firm_up/make_firm.
Google Ngram Viewer shows how "firm up" and "make firm" have occurred on timeline