95 entries under strong topic. ×

25
resistant(adjective, strain, firm, stiff)
22
adamantine(adjective, hard, tough, severe)
22
durable(adjective, strain, firm, stiff)
22
tough(adjective, mean, hard, easy)
20
austere(adjective, hard, tough, severe)
20
solid(adjective, hard, complete, secure)
19
robust(adjective, hard, tough, strain)
18
resilient(adjective, strain, stiff, firmness)
18
withstanding(adjective, strain, stiff, firmness)
15
iron(adjective, mean, hard, tough)
14
implacable(adjective, mean, hard, tough)
13
grim(adjective, hard, tough, severe)
12
mulish(adjective, mean, hard, tough)
12
steely(adjective, hard, tough, firm)
10
flinty(adjective, hard, tough, severe)
9
stiff-necked(adjective, mean, hard, tough)
8
hardheaded(adjective, hard, tough, determined)
7
callous(adjective, set, mean, hard)
7
cruel(adjective, hard, tough, severe)
7
hard-line(adjective, hard, tough, severe)
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APASmart Define. (2015). rigid thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/rigid/thesaurus/synonyms
ChicagoSmart Define. 2015. "rigid thesaurus" https://smartdefine.org/rigid/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, rigid thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/rigid/thesaurus/synonyms>.
MLASmart Define. "rigid thesaurus" 3 August 2015. Web. 25 September 2026. <https://smartdefine.org/rigid/thesaurus/synonyms>