as in to freeze
to become physically firm or solid
wait for the modeling clay to firm up before handling the finished pot
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Example Sentences
Recent Examples of Synonyms for firm (up)
Verb
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The tiny liquid droplets in the fog can freeze instantly to any surface, including vehicles and road surfaces.—
CA Weather Bot,
Sacbee.com,
12 Jan. 2026 -
There’s roughly two and a half months left of the winter season, which means that there are plenty of chilly evenings, snow storms, and freeze warnings to look forward to.—
Amelia McBride,
Travel + Leisure,
11 Jan. 2026
Verb
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For dry or gel polish, use ice to harden it, then gently lift or chip it off.—
Emily Benda Gaylord,
The Spruce,
11 Jan. 2026
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Even Iran’s reformist President Masoud Pezeshkian, who had been trying to ease anger before the demonstrations exploded in recent days, offered a hardening tone in an interview aired Sunday.—
Jon Gambrell,
Los Angeles Times,
11 Jan. 2026
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“Firm (up).” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/firm%20%28up%29. Accessed 12 Jan. 2026.
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