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Definitions

stiffen

[stif-uhn] / ˈstɪf ən /
VERB
make or become harder
Synonyms
STRONGEST
reinforce solidify stabilize strengthen
STRONG
anneal benumb brace cake candy cement chill clot coagulate condense congeal crystallize curdle firm fix freeze gel harden inflate inspissate jell jelly ossify petrify precipitate prop set starch steady tauten tense thicken
Antonyms
STRONGEST
weaken
STRONG
dilute dissolve heat liquefy melt separate soften thin unfix
WEAK
loosen

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.

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 will only stiffen our resolve to ensure that we make Washington DC safe and beautiful," the Pentagon chief said.

From BBC • Nov. 26, 2025

Nonetheless, this is an important move that can help stiffen the spines at other schools.

From Salon • Apr. 16, 2025

Traditionally, the way to stiffen a polymer network is to add more crosslinks.

From Science Daily • Nov. 27, 2024

I felt my mother’s hand stiffen on my shoulder.

From "The Joy Luck Club" by Amy Tan

Vocabulary lists containing stiffen

Mid-Air

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