Clam up
Clam up verb - To stop talking.
Cite this Source
Fasten and Clam up. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/clam_up/fasten
Clam up & Fasten. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/clam_up/fasten>.
Fasten or Clam up. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/clam_up/fasten.
Google Ngram Viewer shows how "clam up" and "fasten" have occurred on timeline