10
invisible(adjective, knowledge, hidden, unable, imperceptible)
8
imperceptible(adjective, knowledge, invisible)
7
impalpable(adjective, knowledge, imperceptible, unsubstantial, intangible)
7
inappreciable(adjective, knowledge, imperceptible)
7
indiscernible(adjective, knowledge, imperceptible, invisible)
7
intangible(adjective, knowledge, indefinite, imperceptible, obscured)
6
insensible(adjective, knowledge, imperceptible)
5
imponderable(adjective, knowledge, imperceptible)
4
unnoticeable(adjective, knowledge, imperceptible)
3
camouflaged(adjective, invisible, latent)
3
concealed(adjective, invisible, latent)
3
covert(adjective, invisible, latent)
3
inconspicuous(adjective, imperceptible)
3
indistinguishable(adjective, knowledge, imperceptible)
3
latent(adjective, invisible, latent)
3
unapparent(adjective, invisible, latent)
2
hidden(adjective, invisible, latent)
2
buried(adjective, latent)
2
evanescent(adjective, imperceptible)
2
indistinct(adjective, imperceptible)
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APASmart Define. (2015). unobservable thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/unobservable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unobservable thesaurus" https://smartdefine.org/unobservable/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, unobservable thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/unobservable/thesaurus/synonyms>.
MLASmart Define. "unobservable thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/unobservable/thesaurus/synonyms>