"cloak-and-dagger activities behind enemy lines"
同义词：clandestinehole-and-corner(a)hugger-muggerhush-hushsecretsurreptitiousundercoverunderground
ADJ（形容词） A cloak-and-dagger activity is one which involves mystery and secrecy. 秘密的; 神秘的 [usu ADJ n]
She was released from prison in a cloak and dagger operation yesterday.
她昨天在一个秘密的行动中被释出狱。