undercover
adj.adj. working in secret to get information, usually for the police or a government. You do this by pretending to be someone else so people do not know your real job.
adj. involved in or involving secret work for investigation or spying, typically by assuming a false identity. Often used to describe law enforcement operations or investigative journalism.
The undercover officer joined the gang to gather evidence.
After months of undercover work, the reporter finally exposed the corruption within the local government.
The success of the sting operation depended entirely on the undercover agent's ability to maintain a convincing persona while operating deep within the criminal organization's inner circle.
From under + cover.
Typically used before a noun; can also follow a linking verb like 'go' ('to go undercover').
he is an undercovered agenthe is an undercover agentLearners sometimes mistakenly add an '-ed' suffix, treating it like a past participle instead of the standard adjective form.