110 entries under adjective topic. ×

4
everlasting(strong, tough)
4
durable(strong, hard, tough, firm)
4
stony(firm, stiff, rigid, unyielding)
4
lasting(strong, tough)
4
eternal
4
unshakable(strong, tough)
3
inviolable
3
permanent
3
strong(hard, firm, solid, stiff)
2
armored(strong, tough)
2
brass-bound(strong, tough)
2
endless
2
good
2
harsh(severe, firm, solid, stiff)
2
imperishable
2
indissoluble
2
indivisible(tenacity, indissoluble)
2
nonbreakable(strong, tough)
2
real
2
secure(strengthened, reinforced)
10 years ago|18k views|share |citing 
APASmart Define. (2016). unbreakable thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/unbreakable/thesaurus/synonyms
ChicagoSmart Define. 2016. "unbreakable thesaurus" https://smartdefine.org/unbreakable/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, unbreakable thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/unbreakable/thesaurus/synonyms>.
MLASmart Define. "unbreakable thesaurus" 5 January 2016. Web. 25 September 2026. <https://smartdefine.org/unbreakable/thesaurus/synonyms>