95 entries under firm topic. ×

8
pertinacious(adjective, tough, difficult, determined)
8
willful(adjective, tough, fast, awkward)
7
pigheaded(adjective, tough, difficult, determined)
7
uncompliant(adjective, tough, stubborn, disobedience)
6
dogged(adjective, tough, determined, unreasonable)
6
immovable(adjective, tough, difficult, determined)
6
incompliant(adjective, hard, tough, difficult)
6
resolute(adjective, tough, difficult, obstinate)
6
tough(adjective, hard, rough, grim)
6
uncompromising(adjective, tough, difficult, violent)
5
balky(tough, negative, hostile, obstinate)
5
cantankerous(adjective, tough, difficult, wild)
5
intransigent(adjective, tough, determined, stubborn)
5
unbending(adjective, hard, tough, rough)
4
bullheaded(adjective, tough, difficult, determined)
4
inexorable(adjective, tough, persistent, obstinate)
4
opinionated(adjective, tough, unreasonable, grim)
4
stiff-necked(adjective, tough, deliberate, determined)
4
untoward(adjective, adverb, control, order, tough)
3
fixed(adjective, hard, tough, rough)
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APASmart Define. (2015). refractory thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/refractory/thesaurus/synonyms
ChicagoSmart Define. 2015. "refractory thesaurus" https://smartdefine.org/refractory/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, refractory thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/refractory/thesaurus/synonyms>.
MLASmart Define. "refractory thesaurus" 10 April 2015. Web. 24 September 2026. <https://smartdefine.org/refractory/thesaurus/synonyms>