70 entries under underground topic. ×

0
cloak-and-dagger(secret, clandestine, undisclosed)
0
closet(secret, clandestine, undisclosed)
0
clouded(clandestine, undisclosed)
0
confidential(secret, clandestine, undisclosed, classified)
0
conspiratorial(clandestine, undisclosed)
0
covered(clandestine, undisclosed)
0
covert(secret, clandestine, undisclosed)
0
deep(clandestine, undisclosed)
0
discreet(clandestine, undisclosed)
0
disguised(clandestine, undisclosed)
0
dissembled(clandestine, undisclosed)
0
dissimulated(clandestine, undisclosed)
0
enigmatical(clandestine, undisclosed)
0
furtive(clandestine, undisclosed)
0
in ambush(expression, clandestine, undisclosed)
0
incognito(clandestine, undisclosed)
0
inside(clandestine, undisclosed)
0
mystic(clandestine, undisclosed)
0
mystical(clandestine, undisclosed)
0
obscure(clandestine, undisclosed)
11 years ago|761 views|share |citing 
APASmart Define. (2015). top-secret thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/top-secret/thesaurus/synonyms
ChicagoSmart Define. 2015. "top-secret thesaurus" https://smartdefine.org/top-secret/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2015, top-secret thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/top-secret/thesaurus/synonyms>.
MLASmart Define. "top-secret thesaurus" 14 April 2015. Web. 29 September 2026. <https://smartdefine.org/top-secret/thesaurus/synonyms>