clandestine Synonyms

secret surreptitious furtive underhand cloak-and-dagger underground private hidden hugger-mugger hole-and-corner sly hush-hush stealthy undercover concealed undergrow back channel subterranean veiled subterrestrial surrey unseen underneath underfoot underhanded privy back room backroom unreported unpublished undisclosed top secret sneakingly under wraps huggermugger sub-rosa surreptitiously conspiratorial clandestinely nonpublic low profile black-market belowground under-the-table behind-the-scenes unrevealed stowaway devious dern deceitful