19
strong(adjective, sound)
12
sturdy
10
tough(adjective, strong, sound)
8
durable
7
heavy(adjective, strong, sound)
7
plausible(adjective, strong, sound)
7
solid(adjective, strong, sound)
6
substantial(adjective, strong, sound)
6
firm(adjective, strong, sound)
5
powerful
5
important
5
reasonable(adjective, strong, sound)
5
likely
5
probable
5
serious(adjective, strong, sound)
5
thick(adjective, strong, sound)
4
convincing(adjective, strong, sound)
4
based on
4
good
4
significant
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APASmart Define. (2016). flimsy thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/flimsy/thesaurus/antonyms
ChicagoSmart Define. 2016. "flimsy thesaurus" https://smartdefine.org/flimsy/thesaurus/antonyms (accessed September 22, 2026).
HarvardSmart Define 2016, flimsy thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/flimsy/thesaurus/antonyms>.
MLASmart Define. "flimsy thesaurus" 26 January 2016. Web. 22 September 2026. <https://smartdefine.org/flimsy/thesaurus/antonyms>