32 entries under solid topic. ×

23
tough(adjective, strong, firm, stiff)
18
flinty(adjective, strong, hard, firm)
18
impenetrable(adjective, firm, stiff, rigid)
8
rigid(adjective, strong, hard, severe, firm)
6
firm(adjective, strong, hard, tough, severe)
5
hard(adjective, strong, severe, firm, harsh)
5
resistant(adjective, strong, hard, tough)
5
tight(adjective, strong, hard, tough)
3
strong(adjective, hard, firm, stiff)
2
harsh(adjective, severe, firm, stiff)
2
stiff(adjective, strong, hard, severe, firm)
1
definite(adjective, severe, firm, harsh)
1
inflexible(adjective, strong, hard, severe, firm)
1
resilient(adjective, strong, hard, stiff)
1
set(adjective, severe, firm, harsh)
0
molded(adjective, strong, hard, stiff)
0
brawny(adjective, strong, hard, stiff)
0
cohesive(adjective, strong, hard, stiff)
0
conditioned(adjective, strong, hard, stiff)
0
dense(adjective, strong, hard, firm)
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APASmart Define. (2016). unbreakable thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/unbreakable/thesaurus/synonyms
ChicagoSmart Define. 2016. "unbreakable thesaurus" https://smartdefine.org/unbreakable/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2016, unbreakable thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/unbreakable/thesaurus/synonyms>.
MLASmart Define. "unbreakable thesaurus" 5 January 2016. Web. 21 September 2026. <https://smartdefine.org/unbreakable/thesaurus/synonyms>