124 entries under tough topic. ×

29
adamantine(adjective, strong, hard, firm)
24
implacable(adjective, mean, strong, hard)
23
intractable(adjective, strong, hard, rough)
23
hard-nosed(adjective, mean, strong, hard, secure)
23
severe(adjective, strong, hard, severe)
21
dogged(adjective, mean, strong, hard)
21
mulish(adjective, mean, strong, hard)
20
inelastic(adjective, hard, firm, solid)
20
stern(adjective, hard, severe, rough)
19
strict(adjective, strong, hard, moderate)
16
grim(adjective, strong, hard, severe)
16
rigorous(adjective, strong, hard, severe)
15
harsh(adjective, mean, strong, hard)
15
iron(adjective, mean, strong, hard)
13
headstrong(adjective, strong, hard, rough)
13
steely(adjective, strong, hard, firm)
12
persistent(adjective, strong, flat, firm)
12
refractory(adjective, hard, rough, firm)
12
set in stone(expression, adjective, idiom, mean, hard)
12
solid(adjective, strong, hard, secure, smooth)
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APASmart Define. (2016). inflexible thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/inflexible/thesaurus/synonyms
ChicagoSmart Define. 2016. "inflexible thesaurus" https://smartdefine.org/inflexible/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2016, inflexible thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/inflexible/thesaurus/synonyms>.
MLASmart Define. "inflexible thesaurus" 24 March 2016. Web. 30 September 2026. <https://smartdefine.org/inflexible/thesaurus/synonyms>