6
nerve(noun, verb, close, set, settle)
5
callous(verb, close, set, settle, firm)
5
caseharden(verb, close, set, continue, firm)
5
coarsen(verb, feel, emotions, calcify, thicken)
5
crystallize(verb, form, close, set, develop)
5
intensify(verb, support, increase, establish, extend)
5
prop(noun, verb, support, increase, sustain)
5
support(noun, verb, increase, establish, extend)
5
vitrify(verb, close, set, settle, firm)
4
adapt(verb, adjust, thicken, stabilize, toughen)
4
adjust(verb, prepare, endure, adapt, thicken)
4
calcify(verb, close, set, settle, firm)
4
conform(verb, adjust, adapt, thicken, stabilize)
4
discipline(verb, study, develop, improve, prepare)
4
familiarize(verb, prepare, endure, adjust, adapt)
4
fossilise
4
gel(verb, form, set, develop, combine)
4
gird(verb, support, close, set, settle)
4
refresh(encourage, strength, stimulate, restore, hearten)
4
sustain(verb, support, increase, keep, overcome)
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APASmart Define. (2016). harden thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/harden/thesaurus/synonyms
ChicagoSmart Define. 2016. "harden thesaurus" https://smartdefine.org/harden/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, harden thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/harden/thesaurus/synonyms>.
MLASmart Define. "harden thesaurus" 24 March 2016. Web. 25 September 2026. <https://smartdefine.org/harden/thesaurus/synonyms>