9
hole-and-corner(adjective, private, hidden, spy, sneaky)
9
innate(adjective, intimate, private, mental, penetrating)
9
restricted(adjective, close, private, hidden, clandestine)
9
underground(adjective, unknown, hidden, spy, concealed)
9
veiled(adjective, hidden, clandestine, concealed, covered)
8
cabalistic(adjective, evil, obscure, strange, humble)
8
camouflaged(adjective, obscure, hidden, clandestine, concealed)
8
essential(adjective, individual, intimate, private, mental)
8
sly(adjective, quiet, dishonest, deceitful, clever)
7
confidence(noun, hint, exclusive, buzz, gossip)
7
cloak-and-dagger(adjective, show, full, hidden, clandestine)
7
incomprehensible(adjective, obscure, dark, strange, uncertain)
7
inmost(adjective, intimate, private, penetrating, personal)
7
lonely(adjective, close, quiet, remote, private)
7
off the record(expression, adjective, idiom, separate, private)
7
strange(adjective, property, new, remote, odd)
7
under wraps(expression, adjective, idiom, adverb, show)
7
underhanded(adjective, dishonest, cunning, deceitful, clandestine)
7
unseen(adjective, unknown, hidden, covered, dormant)
6
autogenous(adjective, inside, central, interior, inner)
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APASmart Define. (2016). secret thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/secret/thesaurus/synonyms
ChicagoSmart Define. 2016. "secret thesaurus" https://smartdefine.org/secret/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, secret thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/secret/thesaurus/synonyms>.
MLASmart Define. "secret thesaurus" 31 March 2016. Web. 24 September 2026. <https://smartdefine.org/secret/thesaurus/synonyms>