91 entries under dark topic. ×

19
obscure(adjective, sophisticated, mysterious, complicated)
19
unfathomable(adjective, hard, knowledge, obscure, difficult)
18
incomprehensible(adjective, knowledge, obscure, solid)
13
unintelligible(adjective, knowledge, obscure, solid)
9
inexplicable(adjective, obscure, solid, strange)
8
mystic(adjective, obscure, solid, superior)
8
occult(adjective, obscure, superior, strange)
7
murky(adjective, obscure, solid, gloomy)
7
unknowable(adjective, obscure, solid, superior)
6
cloudy(adjective, gloomy, dense, misty)
5
hidden(adjective, obscure, difficult, solid)
4
difficult(adjective, obscure, strange, odd)
4
dim(adjective, gloomy, dense, cloudy)
4
uncomprehensible(adjective, knowledge, obscure, superior)
3
dull(adjective, gloomy, dense, cloudy)
2
invisible(obscure, superior, mysterious, supernatural)
2
lowering(gloomy, dirty, dreary, misty)
2
misty(gloomy, dense, cloudy, impervious)
2
numinous(obscure, superior, mysterious, supernatural)
2
secret(adjective, obscure, superior, strange)
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APASmart Define. (2015). impenetrable thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/impenetrable/thesaurus/synonyms
ChicagoSmart Define. 2015. "impenetrable thesaurus" https://smartdefine.org/impenetrable/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2015, impenetrable thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/impenetrable/thesaurus/synonyms>.
MLASmart Define. "impenetrable thesaurus" 10 April 2015. Web. 23 September 2026. <https://smartdefine.org/impenetrable/thesaurus/synonyms>