stiffen
Americanverb (used with object)
verb (used without object)
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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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are stiffeningprogressive
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am 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.
These are, Mr. Freymann writes, “tempting targets,” but seizing them could stiffen the resolve of Taiwan and its Western friends.
From The Wall Street Journal • May 14, 2026
She has also vowed to stiffen prison sentences and to impose a state of emergency in areas worst hit by crime.
From Barron's • Feb. 1, 2026
This involves the buildup of dense, fibrous tissue around the tumor, made up of cells and proteins that stiffen and inflame the area.
From Science Daily • Jan. 30, 2026
Calling the eradication of extortion “one of the great challenges” facing Mexico, Sheinbaum pledged to bolster enforcement, stiffen penalties and increase safeguards for anyone receiving threats.
From Los Angeles Times • Dec. 16, 2025
I saw Danny stiffen in his seat, throw me a quick, almost fearful glance, then look away.
From "The Chosen" by Chaim Potok
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.
