5
flagship(noun, vessel, boat, ship, combatant)
5
flotilla leader(vessel, boat, ship, transportation)
5
front runner(vessel, boat, ship, transportation)
5
inexorable(adjective, cruel, pitiless)
5
invariable(adjective, set, hard, stiff, inflexible)
5
lead ship(vessel, boat, ship, transportation)
5
mother ship(vessel, boat, ship, transportation)
4
hard
4
immutable(adjective, flexible)
4
inalterable(adjective, inflexible, flexible)
4
rigorous
4
stiff(adjective, set, hard, severe, harsh)
4
stubborn(adjective, firm, determined, usual, regular)
4
uncompromising(adjective, fixed, rigid)
3
armored
3
certain(adjective, set, determined, usual, regular)
3
constant
3
definite(adjective, firm, determined, usual, regular)
3
loricated
3
painstaking(adjective, character, behavior, pedant)
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APASmart Define. (2015). ironclad thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/ironclad/thesaurus/synonyms
ChicagoSmart Define. 2015. "ironclad thesaurus" https://smartdefine.org/ironclad/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, ironclad thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/ironclad/thesaurus/synonyms>.
MLASmart Define. "ironclad thesaurus" 13 April 2015. Web. 26 September 2026. <https://smartdefine.org/ironclad/thesaurus/synonyms>