0
exhaustlessness
0
forever and a day(noun, expression, adjective, adverb, age)
0
forever and aye(expression, idiom)
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frequently
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future(noun, age, infinity, perpetuity)
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illimitability
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illimitably
0
immeasurably
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immensely
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immutable(adjective, stable, constant, enduring, lasting)
0
imperishability(noun, age, future, infinity, perpetuity)
0
imperishable(adjective, stable, constant, enduring, lasting)
0
in for the long haul(expression, adjective, idiom, stable, lasting)
0
incalculably
0
incessant(permanent, everlasting, unending, long-term, undying)
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incomprehensibility
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incomprehensibly
0
indefinite(lasting, permanent, everlasting, unending, undying)
0
indefinitely
0
indelible(adjective, permanent, long-term, lifelong)
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APASmart Define. (2015). forever thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/forever/thesaurus/synonyms
ChicagoSmart Define. 2015. "forever thesaurus" https://smartdefine.org/forever/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, forever thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/forever/thesaurus/synonyms>.
MLASmart Define. "forever thesaurus" 15 December 2015. Web. 22 September 2026. <https://smartdefine.org/forever/thesaurus/synonyms>