3
obscured(adjective, secret, hidden, underground, concealed)
3
secretive(adjective, dishonest, cunning, deceitful, mysterious)
3
sly(adjective, quiet, dishonest, cunning, deceitful)
3
stealth(noun, adjective, secret, hidden, spy)
3
under an eclipse(expression, idiom, concealment)
2
esoteric(secret, unknown, hidden, underground, concealed)
2
in ambush(expression, idiom, clandestine, underground, undisclosed)
2
in the dark(expression, idiom, reticent, unknown, taciturn)
2
abstruse(secret, unknown, hidden, underground, concealed)
2
clandestinely(adverb, clandestine, secretly, furtively, slyly)
2
cloaked(obscure, secret, unknown, hidden, clandestine)
2
close(mysterious, private, reticent, unknown, hidden)
2
closet(noun, adjective, secret, sly, clandestine)
2
covered(obscure, secret, unknown, hidden, concealed)
2
creep(adjective, secret, hidden, spy, covert)
2
cryptic(adjective, mysterious, private, reticent, unknown)
2
disorderly
2
feline(mysterious, private, reticent, taciturn, covert)
2
hush hush(expression, idiom)
2
in a cloud(expression, idiom, concealment)
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APASmart Define. (2015). undercover thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/undercover/thesaurus/synonyms
ChicagoSmart Define. 2015. "undercover thesaurus" https://smartdefine.org/undercover/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2015, undercover thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/undercover/thesaurus/synonyms>.
MLASmart Define. "undercover thesaurus" 13 April 2015. Web. 23 September 2026. <https://smartdefine.org/undercover/thesaurus/synonyms>