STIFFEN Synonyms: 9 Similar and Opposite Words

stiffen

verb

ˈsti-fən

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

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Example Sentences

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Recent Examples of stiffen The luxury retailer, weighed down by debt, is under pressure as consumers shift their shopping habits and competition stiffens. —

Brian Womack, Dallas Morning News, 29 Jan. 2026 The Czech Republic’s new government will seek to transform the defense industry into an engine of the nation’s export economy as the flagship auto sector faces stiffening competition, a senior cabinet member said. —

Michal Kubala, Bloomberg, 27 Jan. 2026 Extra material had been sewn into the crotch to stiffen and add surface area that would help during takeoff. —

Brian Melley, Chicago Tribune, 23 Jan. 2026 These include stiffening of blood vessels, changes in heart muscle function and impaired ability of the cardiovascular system to respond to exertion. —

Katia Hetter, CNN Money, 16 Jan. 2026 See All Example Sentences for stiffen

Recent Examples of Synonyms for stiffen

strengthen

Verb

Duffy said the registration system and requirements for trucking companies will be strengthened while Federal Motor Carrier Safety Administration inspectors conduct more spot checks of trucks and commercial driver's license schools.

— Arkansas Online, Arkansas Online, 21 Feb. 2026
His addition also heralded the dawning of an era in which LACMA actively sought to strengthen its connections with the entertainment world.

— Arts Editor, Los Angeles Times, 20 Feb. 2026