21
set(verb, form, support, calm, close)
20
harden(verb, form, support, close, place)
20
solidify(verb, form, close, place, set)
17
congeal(verb, form, close, place, set)
15
thicken(verb, form, close, place, set)
15
tighten(verb, stretch, tense, brace, hunch)
13
jell(verb, close, set, fix, settle)
10
freeze(verb, form, calm, close, set)
10
strengthen(verb, support, dull, close, set)
10
brace(noun, verb, calm, close, set)
10
fortify(verb, support, close, set, fix)
10
tense(verb, stretch, hunch, harden, jellied)
9
coagulate(verb, form, close, set, fix)
9
reinforce(verb, support, close, set, fix)
9
toughen(verb, support, close, set, fix)
8
tauten(verb, stretch, tense, hunch, harden)
7
clot(verb, form, close, set, fix)
7
constrain
7
firm(verb, calm, close, set, fix)
7
fix(verb, calm, close, set, secure)
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APASmart Define. (2015). stiffen thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/stiffen/thesaurus/synonyms
ChicagoSmart Define. 2015. "stiffen thesaurus" https://smartdefine.org/stiffen/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, stiffen thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/stiffen/thesaurus/synonyms>.
MLASmart Define. "stiffen thesaurus" 13 April 2015. Web. 22 September 2026. <https://smartdefine.org/stiffen/thesaurus/synonyms>