stiffen
verb
stiff·en ˈsti-fən 
stiffened; stiffening ˈsti-fə-niŋ
ˈstif-niŋ
transitive verb
: to make stiff or stiffer
intransitive verb
: to become stiff or stiffer
stiffener
ˈsti-fə-nər
noun ˈstif-nər
Synonyms
- harden
- harshen
- strengthen
- toughen
See all Synonyms & Antonyms 
Example Sentences
She stiffened when he grabbed her shoulder. The dogs stiffened in alarm. The law would stiffen penalties for tax evasion.
Recent Examples on the Web If the 93rd gains much more ground, the Russians might wake up to the threat the brigade poses—and send in reinforcements to stiffen local defenses. 
David Axe, Forbes, 9 Aug. 2022 But the report could stiffen the Federal Reserve’s resolve to cool the economy. New York Times, 5 Aug. 2022 This technology was first used in the high-end Concept 500 to stiffen resistance in parts of the speaker cabinet that are particularly susceptible to being affected by low-end frequency reverberations. Mark Sparrow, Forbes, 14 Aug. 2022 So, Goodell is left to appeal to himself to stiffen Watson’s penalty, but in so doing would undermine the decision of the arbiter and would leave the door open for a lawsuit by Watson and the NFLPA in federal court. Ted Crow, cleveland, 3 Aug. 2022 The dough will feel dense and will stiffen into a ball. Becky Krystal, Washington Post, 30 June 2022 Tap the stability-control switch twice to activate WTF mode and wait a few seconds for the truck to lower its air springs, stiffen its adaptive dampers, and prime its systems for the oncoming flood of electrons. Mike Sutton, Car and Driver, 7 Apr. 2022 These changes narrow and stiffen your arteries, increasing the risk of blood clots, heart disease, stroke, heart attack, and kidney disease, per the Centers for Disease Control & Prevention (CDC). Lauren Krouse, Health.com, 20 Oct. 2021 The findings could stiffen employers’ resolve to urge or require their employees to trek back to the office. Bret Stetka, Scientific American, 27 Apr. 2022 See More
David Axe, Forbes, 9 Aug. 2022 But the report could stiffen the Federal Reserve’s resolve to cool the economy. New York Times, 5 Aug. 2022 This technology was first used in the high-end Concept 500 to stiffen resistance in parts of the speaker cabinet that are particularly susceptible to being affected by low-end frequency reverberations. Mark Sparrow, Forbes, 14 Aug. 2022 So, Goodell is left to appeal to himself to stiffen Watson’s penalty, but in so doing would undermine the decision of the arbiter and would leave the door open for a lawsuit by Watson and the NFLPA in federal court. Ted Crow, cleveland, 3 Aug. 2022 The dough will feel dense and will stiffen into a ball. Becky Krystal, Washington Post, 30 June 2022 Tap the stability-control switch twice to activate WTF mode and wait a few seconds for the truck to lower its air springs, stiffen its adaptive dampers, and prime its systems for the oncoming flood of electrons. Mike Sutton, Car and Driver, 7 Apr. 2022 These changes narrow and stiffen your arteries, increasing the risk of blood clots, heart disease, stroke, heart attack, and kidney disease, per the Centers for Disease Control & Prevention (CDC). Lauren Krouse, Health.com, 20 Oct. 2021 The findings could stiffen employers’ resolve to urge or require their employees to trek back to the office. Bret Stetka, Scientific American, 27 Apr. 2022 See More Word History
First Known Use
15th century, in the meaning defined at transitive sense
Kids Definition
stiffen
verb
stiff·en ˈsti-fən
stiffened; stiffening
1
: to make or become stiff or stiffer
The paper stiffened as it dried.
2
: to become tense and still
He stiffened with suspicion.
stiffen
verb
as in to strengthen
to make more harsh, uncompromising, or severe plans to further stiffen the already onerous requirements for admission to the elite military unit Synonyms & Similar Words
Relevance
- strengthen
- harden
- toughen
- harshen
Antonyms & Near Antonyms
- ease
- soften
- lessen
- ameliorate
- moderate