clandestine
source sentence: "Washington also expanded the elaborate clandestine war agiast North Vietnam that it had begun in 1955."
context clues: example clues, inference clues, (syn.) hidden, secretive, (ant.) announced, apparent
definition: characterized by, done in, or executed with secrecy or concealment, esp. for purposes of subversion or deception; private or surreptitious
original sentence: CIA spies are usually very sneaky and clandestine.
http://dictionary.reference.com/browse/clandestine
