stiffen
Americanverb (used with object)
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stiffens,
present (3rd person singular)
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stiffened,
past participle, past
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stiffening
present participle
verb (used without object)
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stiffens,
present (3rd person singular)
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stiffened,
past participle, past
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stiffening
present participle
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to become stiff.
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to become suddenly tense, rigid, or taut, as in bracing oneself for or drawing back from shock, fear, or displeasure.
He stiffened, expecting to hear the worst.
verb
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to make or become stiff or stiffer
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(intr) to become suddenly tense or unyielding
Other Word Forms
Derived Forms
Inflected Forms
Participles
Conjugated Forms
Present
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stiffensimple
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stiffenssimple
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have stiffenedperfect
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has stiffenedperfect
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am stiffeningprogressive
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are stiffeningprogressive
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is stiffeningprogressive
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have been stiffeningperfect progressive
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has been stiffeningperfect progressive
Past
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stiffenedsimple
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had stiffenedperfect
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was stiffeningprogressive
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were stiffeningprogressive
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had been stiffeningperfect progressive
Future
Etymology
Origin of stiffen
Explanation
To stiffen is to become stiff or unbending. If your legs stiffen during a long plane flight, you'll want to stretch them out once you land. You can stiffen something deliberately, like when you stiffen a package with cardboard to protect it in the mail. You can also stiffen in reaction to something: "The spooky creaking sounds upstairs made us stiffen in terror." The earliest sense of this verb was "make steadfast," from a now-obsolete meaning of stiff, "gain strength."
Vocabulary lists containing stiffen
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
“People get scared of the sway, the wobble. If you’ve had a fall before, you get a fear of falling again and you stiffen up, you become protective,” Swanson says.
From Los Angeles Times ● Aug. 18, 2026
This summer, Slegers has strengthened her hand with seven new players, including full-back Ona Batlle, Caldentey's compatriot, and England dynamo Georgia Stanway to stiffen midfield.
From BBC ● Aug. 7, 2026
This approach enabled us to create a material that can bend, buckle, or stiffen differently under slow movements versus sudden impacts -- without electronics, sensors, or active control.
From Science Daily ● Jun. 11, 2026
“It probably would stiffen their spine,” said Brian Latell, a former CIA analyst who wrote a biography of Castro and his older brother Fidel Castro.
From The Wall Street Journal ● May 21, 2026
On the surface, the water seems to stiffen and turn greasy.
From "Shipwreck at the Bottom of the World" by Jennifer Armstrong
Once the pH returns to normal, the tissue stiffens again and locks into its new form.
From Science Daily ● May 28, 2026
The biggest reason is that our maximum heart rate slows with age, and the heart muscle stiffens, reducing its pumping effectiveness.
From Barron's ● May 23, 2026
Last year, Alibaba announced a plan to fold food-delivery and online-travel services into its e-commerce unit as competition stiffens in the Chinese market.
From The Wall Street Journal ● Jan. 29, 2026
"Everyone, by the time you get to your mid-30s, maybe early 40s, you'll notice that the lens of the eye really stiffens," she said.
From BBC ● Nov. 29, 2025
She stiffens at first—must’ve caught her off guard—but then she says, “Me too, Rae. I’m glad, too.”
From "Odd One Out" by Nic Stone
The Romans, their ranks stiffened by Genoese and Venetian troops, did their best to resist.
From The Wall Street Journal ● Aug. 5, 2026
Others argued the particles stiffened the surrounding material like glue.
From Science Daily ● May 13, 2026
They reckon it may have stiffened the resolve of the German public and discouraged rebels within the dying Nazi regime.
From MarketWatch ● Mar. 12, 2026
Johnson’s move appears to have stiffened investors’ spines.
From Barron's ● Feb. 11, 2026
Charlie stiffened, stared straight ahead and rattled off the formula.
From "Carry On, Mr. Bowditch" by Jean Lee Latham
Softening rather than stiffening when moving through space requires embracing your body’s natural sway and tiny micro-movements, like an ankle wobbling or knee jiggling.
From Los Angeles Times ● Aug. 18, 2026
IPF is a chronic, progressive lung disease characterized by irreversible scarring and stiffening of lung tissue.
From Barron's ● Mar. 30, 2026
It’s hard to imagine a greater accomplishment than to achieve peace while stiffening the sinews of deterrence.
From The Wall Street Journal ● Mar. 1, 2026
These findings further support the idea that chronic inflammation drives tissue stiffening.
From Science Daily ● Jan. 24, 2026
When Diana came her way, Lyddie could feel herself stiffening up.
From "Lyddie" by Katherine Paterson
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
