39 entries under obscure topic. ×

9
covered(adjective, unknown, hidden, concealed)
7
cloak-and-dagger(adjective, unknown, hidden, clandestine)
7
furtive(adjective, secret, unknown, hidden)
6
private(adjective, secret, unknown, hidden)
5
deep(adjective, down, unknown, far)
5
secluded(adjective, secret, unknown, hidden)
4
clouded(secret, unknown, hidden, concealed)
4
mysterious(adjective, secret, unknown, hidden)
4
occult(noun, secret, unknown, hidden)
2
abstruse(secret, unknown, hidden, concealed)
2
close(secret, unknown, hidden, concealed)
2
closet(unknown, hidden, clandestine, fraudulent)
2
mystic(adjective, secret, unknown, hidden)
2
mystical(adjective, secret, unknown, hidden)
2
recondite(secret, unknown, hidden, concealed)
2
undisclosed(adjective, secret, unknown, hidden)
2
unknown(secret, hidden, concealed, unseen)
1
classified(unknown, clandestine, undisclosed, unrevealed)
1
cryptic(secret, unknown, hidden, concealed)
1
esoteric(secret, unknown, hidden, concealed)
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APASmart Define. (2015). underground thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/underground/thesaurus/synonyms
ChicagoSmart Define. 2015. "underground thesaurus" https://smartdefine.org/underground/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, underground thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/underground/thesaurus/synonyms>.
MLASmart Define. "underground thesaurus" 3 November 2015. Web. 25 September 2026. <https://smartdefine.org/underground/thesaurus/synonyms>