Synonyms|251Antonyms|39|Broader|2Narrower|0Related|383
1
unmovable
1
unpliable
1
unsentimental
1
unsparing(adjective, strong, hard, tough, sturdy)
1
unswerving(adjective, determined, resolute, uncompromising, unshakeable)
1
unsympathetic
1
unvarying
1
well-built
1
well-grounded
1
well-made
0
armored(adjective, strong, tough, permanent, strengthened)
0
astringent(adjective, strong, hard, tough, sturdy)
0
bad
0
bitter(adjective, strong, hard, tough, sturdy)
0
bolshie
0
bony
0
buckram
0
by the book(expression, adjective, idiom, strong, hard)
0
calculous
0
cartilaginous
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APASmart Define. (2015). adamantine thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/adamantine/thesaurus/synonyms
ChicagoSmart Define. 2015. "adamantine thesaurus" https://smartdefine.org/adamantine/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, adamantine thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/adamantine/thesaurus/synonyms>.
MLASmart Define. "adamantine thesaurus" 10 April 2015. Web. 24 September 2026. <https://smartdefine.org/adamantine/thesaurus/synonyms>