4
imagined(fake, false, negative, imaginary, fanciful)
4
imponderable(adjective, light, weak, slight, negative)
4
insipid(adjective, light, soft, pastel)
4
nonexistent(adjective, fake, false, real, imaginary)
4
precarious(unstable, vulnerable, dangerous, unprotected, unguarded)
4
sleazy(adjective, weak, slight, thin, feeble)
4
subtle(slight, small, miserable, inadequate, limited)
4
unconvincing(adjective, weak, flat, poor, thin)
4
unsteady(adjective, false, uncertain, unstable, ill)
4
weightless(adjective, light, slight, easy, thin)
3
brittle(adjective, weak, delicate, infirm, flimsy)
3
cranky(adjective, weakness, strange, fantasy, unreal)
3
creaky(weakness, feeble, frail, flimsy, debilitated)
3
delusory(adjective, strange, fantasy, unreal)
3
dilapidated(adjective, feeble, frail, flimsy, debilitated)
3
dreamlike(adjective, fake, false, negative, imaginary)
3
evanescent
3
faint(adjective, dull, light, weak, soft)
3
flashy
3
fleeting
10 years ago|18k views|share |citing 
APASmart Define. (2016). insubstantial thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/insubstantial/thesaurus/synonyms
ChicagoSmart Define. 2016. "insubstantial thesaurus" https://smartdefine.org/insubstantial/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, insubstantial thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/insubstantial/thesaurus/synonyms>.
MLASmart Define. "insubstantial thesaurus" 30 March 2016. Web. 25 September 2026. <https://smartdefine.org/insubstantial/thesaurus/synonyms>