19 entries under hardened topic. ×

10
chronic(adjective, persistent, enduring, lasting)
10
lifelong(adjective, familiar, established, enduring)
6
inveterate(adjective, familiar, established, enduring)
6
old(adjective, continue, familiar, established)
5
long-standing(adjective, continue, persistent, continuous)
3
habitual(adjective, persistent, continuous, lasting)
2
persisting(persistent, continuous, lasting, permanent)
1
confirmed(persistent, continuous, lasting, continuing)
1
deep-rooted(persistent, continuous, lasting, permanent)
1
deep-seated(persistent, continuous, lasting, continuing)
1
fixed(adjective, stable, persistent, constant)
1
inbred(persistent, continuous, lasting, continuing)
1
incurable(persistent, continuous, lasting, continuing)
1
ineradicable(adjective, persistent, continuous, lasting)
1
ingrained(persistent, continuous, lasting, continuing)
1
obstinate(persistent, continuous, lasting, continuing)
1
set(stable, constant, enduring, lasting)
1
settled(persistent, continuous, lasting, continuing)
1
usual(persistent, continuous, lasting, continuing)
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APASmart Define. (2015). perennial thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/perennial/thesaurus/synonyms
ChicagoSmart Define. 2015. "perennial thesaurus" https://smartdefine.org/perennial/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2015, perennial thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/perennial/thesaurus/synonyms>.
MLASmart Define. "perennial thesaurus" 10 April 2015. Web. 30 September 2026. <https://smartdefine.org/perennial/thesaurus/synonyms>