891 entries under adjective topic. ×

42
resistant(strong, tough, strain, fit)
41
unshakable(mean, strong, hard, complete)
40
solid(calm, good, close, set)
39
staying(strain, firmness, labour, hardiness)
38
impregnable(strain, true, firmness, constant)
38
perpetual(strain, determined, familiar, steady)
38
quiescent(strain, firmness, labour, hardiness)
38
stabile(calm, strong, secure, strain)
38
sustained(strain, firmness, persistent, continuous)
37
conservative(moderate, strain, firmness, cautious)
37
insistent(set, determined, steady, resolute)
37
long-standing(strain, firmness, labour, hardiness)
37
resilient(strain, firmness, labour, hardiness)
37
stabilized(strain, firmness, labour, hardiness)
37
tenable(strain, firmness, labour, hardiness)
37
well-balanced(strain, firmness, labour, hardiness)
36
abundant(strain, firmness, labour, hardiness)
36
immune(strain, firmness, safe, labour)
36
non-fluctuating(strain, firmness, labour, hardiness)
36
proof(strain, firmness, labour, hardness)
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APASmart Define. (2016). firm thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/firm/thesaurus/synonyms
ChicagoSmart Define. 2016. "firm thesaurus" https://smartdefine.org/firm/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, firm thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/firm/thesaurus/synonyms>.
MLASmart Define. "firm thesaurus" 31 March 2016. Web. 25 September 2026. <https://smartdefine.org/firm/thesaurus/synonyms>