Synonyms of undercover

Adjective

1. clandestine, cloak-and-dagger, hole-and-corner(prenominal), hugger-mugger, hush-hush, secret, surreptitious, undercover, underground, covert (vs. overt)

usage: conducted with or marked by hidden aims or methods; "clandestine intelligence operations"; "cloak-and-dagger activities behind enemy lines"; "hole-and-corner intrigue"; "secret missions"; "a secret agent"; "secret sales of arms"; "surreptitious mobilization of troops"; "an undercover investigation"; "underground resistance"

Definition and meaning of undercover (Dictionary)