undercover

/ˌʌndərˈkʌvər/
adjective
  1. Working or done secretly, especially to investigate or catch criminals.
    • She worked as an undercover journalist to expose the corruption.
    • The police used an undercover officer to buy illegal weapons.
    • The detective went undercover to infiltrate the drug ring.
Antonyms
adverb
  1. In a secret way, especially as part of an investigation.
    • They operated undercover for months before making any arrests.
    • He went undercover to gather evidence against the gang.
    • The agent was living undercover in the neighborhood.
What does "undercover" mean? | whatsthatwordmean | whatsthatwordmean