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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.

Chinese leader Xi Jinping has said that young people should stiffen their spines and embrace hardship.

From The Wall Street Journal • Apr. 28, 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

In people with Alzheimer's, Aβ accumulates and causes arteries to stiffen, slowing the flow of fluids between brain tissue and cerebrospinal fluid.

From Science Daily • Nov. 11, 2025

The effort to scrap the provision to stiffen penalties drew sweeping criticism from the governor and on social media.

From Los Angeles Times • May 1, 2025

I stiffen and shove a spoonful of food into my mouth, refusing to look at her.

From "An Ember in the Ashes" by Sabaa Tahir

Vocabulary lists containing stiffen

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