Marked by menacing furtive secrecy, often with a melodramatic tint or espionage involved
Israel wages cloak-and-dagger war on Iran — headline, The Age, February 18, 2009 by Philip Sherwell and Dina Kraft.
A cloak-and-dagger activity is one which involves mystery and secrecy. She was released from prison in a cloak and dagger operation yesterday. very secret and mysterious, and usually involving the work of spies
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"