1
as in to freeze
to become physically firm or solid
the glue begins to harden as soon as it is exposed to air
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2
as in to strengthen
to make able to withstand physical hardship, strain, or exposure
pioneer women who had been hardened by years of living on the plains
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3
as in to toughen
to increase the ability of (as a muscle) to exert physical force
arm muscles that were hardened by all the years of casting and hauling his fishing nets
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4
as in to stiffen
to make more harsh, uncompromising, or severe
the government hardened restrictions on travel to and from the war-torn nation
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Example Sentences
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Recent Examples of harden
Synthetic versions harden even more into a durable, heat-resistant material used in everything from adhesives and coatings to plastics and electronics.
—
Kevin Williams, CNBC, 7 June 2026
Dark lunar maria are visible sprawling across the moon's surface, where lava once rose to the surface before hardening to form enormous basaltic plains.
—Anthony Wood, Space.com, 1 June 2026
Vegas has had a more challenging path to the final and might be more playoff-hardened at the moment.
—Pierre Lebrun, New York Times, 1 June 2026
To-Do Checklist Stop fertilizing woody shrubs and ornamental trees at the end of the month to allow new growth to harden off before fall weather.
—Andy Wilcox, Better Homes & Gardens, 31 May 2026
See All Example Sentences for harden
Kevin Williams, CNBC, 7 June 2026
Dark lunar maria are visible sprawling across the moon's surface, where lava once rose to the surface before hardening to form enormous basaltic plains.
—Anthony Wood, Space.com, 1 June 2026
Vegas has had a more challenging path to the final and might be more playoff-hardened at the moment.
—Pierre Lebrun, New York Times, 1 June 2026
To-Do Checklist Stop fertilizing woody shrubs and ornamental trees at the end of the month to allow new growth to harden off before fall weather.
—Andy Wilcox, Better Homes & Gardens, 31 May 2026
See All Example Sentences for harden
Recent Examples of Synonyms for harden
Verb
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The harder question, raised again and again at the conference, is how to write sensible rules without freezing the experimentation that makes the technology worth having.—
Dara-Abasi Ita,
Forbes.com,
12 June 2026
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Cover tightly with plastic wrap and freeze at least 6 hours (or up to 7 days).—
Katlyn Moncada,
Better Homes & Gardens,
12 June 2026
Verb
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The national initiative is awarding more than $10 million to help small businesses grow, innovate, and strengthen their local communities, a spokesperson from the grant program said.—
Pamela McLoughlin,
Hartford Courant,
12 June 2026
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Not only does the brand’s shampoo and conditioner make my hair feel so clean and look so shiny, but both formulas are also jam-packed with strengthening ingredients—avocado oil, olive oil, milk thistle, and growth-stimulating rosemary—that make the combo genuinely feel like a worthwhile luxury.—
Olivia Cigliano,
InStyle,
12 June 2026
Verb
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To execute its ruthless 66-pound weight loss program, the rear seats have been completely deleted, replaced by a massive structural strut brace that significantly stiffens the chassis.—
Peter Lyon,
Forbes.com,
13 June 2026
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Nicks on the edge or stiffened, curled rubber will leave streaks.—
Mary Marlowe Leverette,
Southern Living,
12 June 2026
Cite this Entry
“Harden.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/harden. Accessed 17 Jun. 2026.
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