275 entries under solid topic. ×

28
sturdy(adjective, calm, strong, hard, sound)
26
unfaltering(adjective, strong, complete, total)
24
secure(verb, adjective, calm, fix, strong)
23
unswerving(adjective, close, strong, tough, correct)
22
sure(adjective, calm, good, close, clear)
21
dogged(adjective, mean, strong, hard, tough)
21
established(adjective, definite, strong, state, calm)
19
reliable(adjective, calm, close, clear, strong)
18
certain(adjective, characteristic, good, change, clear)
17
definite(adjective, good, clear, strong, complete)
17
faithful(adjective, good, close, strong, correct)
16
dense(adjective, set, strong, hard, tough)
15
unchanging(adjective, close, correct, moderate, severe)
14
devoted(adjective, good, close, strong, correct)
14
positive(adjective, good, clear, strong, complete)
14
true(adjective, good, close, clear, strong)
14
unchangeable(adjective, calm, strong, secure, moderate)
12
compact(verb, adjective, close, set, fix)
12
concrete(verb, adjective, close, set, clear)
12
dependable(adjective, good, close, strong, tough)
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APASmart Define. (2016). firm thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/firm/thesaurus/synonyms
ChicagoSmart Define. 2016. "firm thesaurus" https://smartdefine.org/firm/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2016, firm thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/firm/thesaurus/synonyms>.
MLASmart Define. "firm thesaurus" 31 March 2016. Web. 23 September 2026. <https://smartdefine.org/firm/thesaurus/synonyms>