Thesaurus.com
Dictionary.com
Showing results for stiffen. Search instead for stifteten.
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 leads the muscles to weaken and stiffen over time and ultimately impacts how you walk, talk, eat and breathe.

From BBC • Dec. 4, 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

My mother could see that I really wasn’t in one piece after all, so she listened quietly, stroking my hair as I talked, but gradually I could feel her stiffen.

From "Homesick" by Jean Fritz

Vocabulary lists containing stiffen

Mid-Air

Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!