178 entries under tough topic. ×

13
unsympathetic(adjective, mean, hard, cool)
12
heartless(adjective, mean, feeling, hard, cool)
12
steely(adjective, strong, hard, cold)
11
flinty(adjective, close, strong, hard)
11
opinionated(adjective, firm, determined, resolute)
11
persistent(adjective, strong, flat, firm)
10
rigorous(adjective, strong, hard, severe)
9
austere(adjective, mean, strong, hard)
9
cold-blooded(adjective, person, mean, hard, cool)
9
hardheaded(adjective, strong, hard, determined)
9
merciless(adjective, person, mean, hard)
9
pitiless(adjective, mean, hard, severe)
9
refractory(adjective, firm, difficult, determined)
9
strict(adjective, strong, hard, severe)
9
uncompassionate(adjective, person, mean, hard, cool)
8
cold(adjective, mean, hard, cool)
8
cruel(adjective, mean, strong, hard, cool)
8
dour(adjective, close, hard, severe)
8
ruthless(adjective, mean, hard, severe)
7
bullheaded(adjective, strong, hard, deliberate)
10 years ago|19k views|share |citing 
APASmart Define. (2016). obdurate thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/obdurate/thesaurus/synonyms
ChicagoSmart Define. 2016. "obdurate thesaurus" https://smartdefine.org/obdurate/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2016, obdurate thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/obdurate/thesaurus/synonyms>.
MLASmart Define. "obdurate thesaurus" 23 March 2016. Web. 29 September 2026. <https://smartdefine.org/obdurate/thesaurus/synonyms>