1
eternal(vast, permanent, recurrent, perpetual, long-term)
1
everlasting(vast, permanent, recurrent, perpetual, long-term)
1
forever(vast, permanent, long-term, lifelong, diurnal)
1
hoary
1
in for the long haul(expression, idiom, vast, permanent, long-term)
1
incessant(permanent, recurrent, perpetual, long-term, lifelong)
1
indelible(permanent, long-term, lifelong)
1
indissoluble(permanent, long-term, lifelong)
1
inexhaustible(permanent, long-term, lifelong)
1
inexpungible(vast, permanent, long-term, lifelong, diurnal)
1
lifelong(adjective, permanent, recurrent, perpetual, long-term)
1
long-lasting(permanent, recurrent, perpetual, long-term, lifelong)
1
long-term(vast, permanent, lifelong, diurnal, ceaselessly)
1
longer
1
obsolete
1
olden
1
outdated
1
perdurable(fundamental, permanent, continuing, operating, recurrent)
1
permanent(vast, recurrent, perpetual, long-term, lifelong)
1
perpetual(permanent, recurrent, long-term, lifelong, returning)
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APASmart Define. (2013). longstanding thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/longstanding/thesaurus/synonyms
ChicagoSmart Define. 2013. "longstanding thesaurus" https://smartdefine.org/longstanding/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2013, longstanding thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/longstanding/thesaurus/synonyms>.
MLASmart Define. "longstanding thesaurus" 27 June 2013. Web. 21 September 2026. <https://smartdefine.org/longstanding/thesaurus/synonyms>