70 entries under underground topic. ×

1
recondite(adjective, obscure, unknown, clandestine)
1
reticent(obscure, deep, unknown, clandestine)
1
retired(obscure, deep, unknown, clandestine)
1
secretive(adjective, clandestine, undisclosed)
1
shrouded(adjective, obscure, unknown, clandestine)
1
sly(adjective, clandestine, undisclosed)
1
stealthy(adjective, clandestine, undisclosed)
1
surreptitious(adjective, clandestine, undisclosed)
1
underhand(adjective, clandestine, undisclosed)
1
unenlightened(obscure, deep, unknown, clandestine)
1
unfrequented(obscure, deep, unknown, clandestine)
0
abstruse(obscure, unknown, clandestine, undisclosed)
0
ambiguous(obscure, deep, unknown, clandestine)
0
arcane(obscure, deep, unknown, clandestine)
0
backstairs(clandestine, undisclosed)
0
camouflaged(obscure, unknown, clandestine, undisclosed)
0
cloak-and-dagger(obscure, unknown, clandestine, undisclosed)
0
close(obscure, unknown, clandestine, undisclosed)
0
closet(obscure, unknown, clandestine, undisclosed)
0
clouded(obscure, unknown, clandestine, undisclosed)
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APASmart Define. (2015). unpublished thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/unpublished/thesaurus/synonyms
ChicagoSmart Define. 2015. "unpublished thesaurus" https://smartdefine.org/unpublished/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, unpublished thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/unpublished/thesaurus/synonyms>.
MLASmart Define. "unpublished thesaurus" 14 April 2015. Web. 24 September 2026. <https://smartdefine.org/unpublished/thesaurus/synonyms>