ˌcloak-and-ˈdagger adjective [usually before noun]
very secret and mysterious, and usually involving the work of SPIES:
a cloak-and-dagger operation

[TahlilGaran] Dictionary of Contemporary English ▲

cloak-and-dagger
cloak-and-dagger behaviour is when people behave in a very secret way, often when it is not really necessary.
Is all this cloak-and-dagger stuff necessary? Why can't we just meet in a cafй like everyone else?
(always before noun)

[TahlilGaran] English Idioms Dictionary ▲

cloak-and-dagger
involving secercy and plotting
The agents were involved in cloak-and-dagger diplomacy over the spy scandal.

[TahlilGaran] English Idioms Dictionary ▲

cloak and dagger
adj. Of or about spies and secret agents.
It was a cloak-and-dagger story about some spies who tried to steal atomic secrets.
The book was written by a retired colonel who used to take part in cloak-and-dagger plots. (From the wearing of cloaks and daggers by people in old adventure stories.)
Compare: BLOOD AND THUNDER.

[TahlilGaran] English Idioms Dictionary ▲