95 entries under firm topic. ×

46
stiff(adjective, hard, tough, strain, rough)
43
stubborn(adjective, characteristic, quality, obstinate, stubbornness)
43
hard(adjective, tough, strain, rough)
36
unyielding(adjective, hard, tough, strain, rough)
32
intractable(adjective, control, order, tough, difficulty)
28
rigid(adjective, hard, tough, strain)
25
contumacious(adjective, tough, determined, negative)
24
resistant(adjective, strain, solid, firmness)
22
headstrong(adjective, tough, determined, negative)
19
rebellious(adjective, tough, negative, obstinate)
19
tight(adjective, strain, solid, firmness)
17
perverse(adjective, mean, tough, difficulty)
16
insubordinate(adjective, tough, negative, hostile)
14
self-willed(adjective, tough, difficult, wild)
12
inflexible(adjective, hard, tough, rough)
11
mulish(adjective, tough, difficult, determined)
10
obdurate(adjective, tough, difficult, determined)
10
tenacious(adjective, tough, difficult, wild)
9
adamant(adjective, tough, determined, unreasonable)
9
determined(adjective, tough, persistent, impulsive)
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APASmart Define. (2015). refractory thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/refractory/thesaurus/synonyms
ChicagoSmart Define. 2015. "refractory thesaurus" https://smartdefine.org/refractory/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, refractory thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/refractory/thesaurus/synonyms>.
MLASmart Define. "refractory thesaurus" 10 April 2015. Web. 22 September 2026. <https://smartdefine.org/refractory/thesaurus/synonyms>