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

Synonyms & Similar Words

Relevance

Antonyms & Near Antonyms

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of stiffen Your Cardiovascular Health Can Improve Quickly Arteries naturally stiffen with age, which can raise your risk of heart attack and stroke. —

Md Published, Verywell Health, 11 Apr. 2026 The men’s Run 900 Ultra Black Shorts feature integrated Rheon technology, a reactive polymer that remains soft at rest but stiffens under pressure. —

Alexandra Harrell, Footwear News, 10 Apr. 2026 June stiffened, a pillar of ice. —

Meredith Maran, Los Angeles Times, 8 Apr. 2026 Officials this year have increased restrictions on flying drones and stiffened the penalties for their unauthorized use—including jail time. —

Andrew Nusca, Fortune, 6 Apr. 2026 See All Example Sentences for stiffen

Recent Examples of Synonyms for stiffen

strengthen

Verb

Nexstar contends the deal would strengthen TV station economics, allowing stations to bolster their news gathering and expand the number of newscasts.

— Meg James, Los Angeles Times, 1 May 2026
The medication can help strengthen the floor-of-mouth muscles, keeping the dog’s airway more open.

— Taneia Surles, USA Today, 1 May 2026