undercover

Từ điển WordNet v3.1 - WordNet Dictionary

adjective

conducted with or marked by hidden aims or methods (Freq. 1)
- 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
• Syn:
clandestine, cloak-and-dagger, hole-and-corner, hugger-mugger, hush-hush,
secret, surreptitious, underground
• Similar to:
covert
• Derivationally related forms:
underground (for: underground)

• Từ đồng nghĩa / Synonyms:
  clandestine, cloak-and-dagger, hole-and-corner(a), hugger-mugger, hush-hush, secret, surreptitious, underground