7
incredible(adjective, extraordinary, strange, unreasonable, fantasy)
7
spectral(adjective, dull, light, soft, poor)
7
spiritual(adjective, body, abstract, heavenly, theoretical)
7
trivial(adjective, light, weak, soft, slight)
7
unconvincing(adjective, thin, extraordinary, strange, unreasonable)
7
unstable(adjective, weak, delicate, false, ill)
7
unsteady(adjective, false, uncertain, unstable, ill)
6
ephemeral(light, weak, slight, frail, imaginary)
6
insecure(adjective, weak, delicate, false, unstable)
6
jerry-built(adjective, flimsy)
6
metaphysical(adjective, body, light, weak, slight)
6
nonmaterial(adjective, abstract, heavenly, theoretical, abstruse)
6
nonphysical(adjective, body, abstract, heavenly, theoretical)
6
paltry(adjective, weak, small, insignificant, unimportant)
6
poor(adjective, dull, light, weak, soft)
6
trifling(adjective, light, weak, soft, slight)
5
aerial(adjective, light, weak, slight, substance)
5
breakable(adjective, weak, delicate, feeble, infirm)
5
delusional(adjective, strange, fantasy, unreal)
5
delusory(adjective, strange, fantasy, unreal)
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APASmart Define. (2016). unsubstantial thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/unsubstantial/thesaurus/synonyms
ChicagoSmart Define. 2016. "unsubstantial thesaurus" https://smartdefine.org/unsubstantial/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, unsubstantial thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/unsubstantial/thesaurus/synonyms>.
MLASmart Define. "unsubstantial thesaurus" 30 March 2016. Web. 25 September 2026. <https://smartdefine.org/unsubstantial/thesaurus/synonyms>