4
continued(adjective, steady, stable, regular, constant)
4
eterne(adjective, continue, archaism)
4
even(verb, adjective, sound, steady, stable)
4
exhaustless
4
immemorial(adjective, infinite)
4
indissoluble(adjective, enduring, permanent, everlasting, eternal)
4
intermittent(adjective, regular, normal, continuous, lasting)
4
lengthy(adjective, durable)
4
long-term(adjective, permanent, lifelong)
4
measureless(adjective, constant, absolute, abundant, unrestrained)
4
monotonous(adjective, steady, stable, regular, fixed)
4
never-ceasing(adjective, present, continuous, lasting, continual)
4
numberless(adjective, regular, normal, absolute, abundant)
4
round-the-clock(adjective, continue, continual)
4
termless(adjective, infinite, infinity)
4
undeviating(adjective, continuous)
3
immense(adjective, infinity)
3
incomprehensible
3
intransient
3
livelong(adjective, durable, diuturnity)
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APASmart Define. (2016). perpetual thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/perpetual/thesaurus/synonyms
ChicagoSmart Define. 2016. "perpetual thesaurus" https://smartdefine.org/perpetual/thesaurus/synonyms (accessed September 27, 2026).
HarvardSmart Define 2016, perpetual thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/perpetual/thesaurus/synonyms>.
MLASmart Define. "perpetual thesaurus" 30 March 2016. Web. 27 September 2026. <https://smartdefine.org/perpetual/thesaurus/synonyms>