undercover
adjective [ before noun ] uk/ˌʌn.dəˈkʌv.ər/ us/ˌʌn.dɚˈkʌv.ɚ/
（为给警察或政府搜集情报）秘密工作的，私下进行的
working secretly using a false appearance in order to get information for the police or government
an undercover police operation 警方的秘密行动
an undercover detective 便衣侦探
Synonyms: clandestine cloak-and-daggerhush-hush secret surreptitious
Compare: underground adjective adverb
- More examples
- She doesn't know Jack is an undercover police agent attempting to infiltrate her group.
- As an undercover officer in the Miami police department, your job is to track down an international gang of car thieves.
- Prosecutors have long relied on witnesses, phone taps, and undercover surveillance.