undercover
- adj. 秘密的，秘密从事的；从事间谍活动的
英英释意
- 1. 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"