1
insusceptible of change(expression, idiom)
1
intent(strong, certain, definite, resolved)
1
intractile
1
intransmutable
1
iron
1
irreconcilable
1
irreparable
1
irresilient
1
irresistible(adjective, expected, predictable, necessary, inexorable)
1
last
1
like the Rock of Gibralter(expression, adjective, idiom, steady, stable)
1
locked in(expression, fixed, stiff, impassive, inflexible)
1
long-lasting
1
methodical(adjective, even, rigid, inflexible, reliable)
1
monochrome(adjective, dull, steady, stable, regular)
1
monophonic(adjective, dull, steady, stable, regular)
1
monotonous(adjective, dull, set, steady, stable)
1
nailed(calm, strong, solid, certain, steady)
1
necessary(expected, predictable, inexorable, required, obligatory)
1
no ifs ands or buts(expression, expected, predictable, necessary, inexorable)
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APASmart Define. (2015). unalterable thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/unalterable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unalterable thesaurus" https://smartdefine.org/unalterable/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, unalterable thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/unalterable/thesaurus/synonyms>.
MLASmart Define. "unalterable thesaurus" 13 April 2015. Web. 22 September 2026. <https://smartdefine.org/unalterable/thesaurus/synonyms>