Become obdurate
Harden and become obdurate are semantically related. In some cases you can use "Harden" instead a verb phrase "Become obdurate".
Harden
Harden verb - To become physically firm or solid.
Become obdurate and harden are semantically related. You can use "Become obdurate" instead a verb "Harden".
Cite this Source
Harden and Become obdurate. (2017). Retrieved 2026, August 13, from https://thesaurus.plus/related/become_obdurate/harden
Become obdurate & Harden. N.p., 2017. Web. 13 Aug. 2026. <https://thesaurus.plus/related/become_obdurate/harden>.
Harden or Become obdurate. 2017. Accessed August 13, 2026. https://thesaurus.plus/related/become_obdurate/harden.
Google Ngram Viewer shows how "become obdurate" and "harden" have occurred on timeline