9
secret
5
hidden
5
covert(adjective, clandestine, underhanded)
4
private
4
ulterior(adjective, secret, public, pertaining)
3
clandestine
3
concealed
3
conniving
3
disguised
3
furtive
3
invisible
2
subterranean
2
subterraneous
2
surreptitious
2
undercover
2
underground
2
undisclosed
1
black
1
hole-and-corner
1
backstair
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APASmart Define. (2015). overt thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/overt/thesaurus/antonyms
ChicagoSmart Define. 2015. "overt thesaurus" https://smartdefine.org/overt/thesaurus/antonyms (accessed September 21, 2026).
HarvardSmart Define 2015, overt thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/overt/thesaurus/antonyms>.
MLASmart Define. "overt thesaurus" 10 April 2015. Web. 21 September 2026. <https://smartdefine.org/overt/thesaurus/antonyms>