135 entries under adjective topic. ×

12
sound(calm, good, strong, secure)
11
just(good, sound, right, reasonable)
11
solid(calm, good, strong, sound)
10
valid(good, sound, right, reasonable)
10
well-grounded(good, reason, proper, logical)
9
cogent(good, sound, correct, reasonable)
9
plausible(true, probable)
7
rational(sound, reasonable, reason, logical)
7
reasonable(sound, correct, reason, sensible)
7
reliable(calm, good, strong, secure)
7
strong(calm, good, sound, right)
6
firm(calm, strong, sound, heavy)
6
legitimate(good, sound, right, reasonable)
6
likely(true, probable)
6
secure(calm, good, strong, sound)
6
sensible(reasonable, reason, natural, valid)
6
stable(strong, sound, secure, tough)
6
substantial(calm, good, strong, sound)
6
tenable(reasonable, justified, defensible)
5
sane(reason, sane)
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APASmart Define. (2016). well-founded thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/well-founded/thesaurus/synonyms
ChicagoSmart Define. 2016. "well-founded thesaurus" https://smartdefine.org/well-founded/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2016, well-founded thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/well-founded/thesaurus/synonyms>.
MLASmart Define. "well-founded thesaurus" 29 March 2016. Web. 26 September 2026. <https://smartdefine.org/well-founded/thesaurus/synonyms>