undercover
- 01 B2 Upper Intermediate
adj.working secretly to get information, especially for the police or government.
adj.involved in or involving secret investigation or spying, typically while assuming a false identity.
Simple“The undercover officer spent months living with the gang to gather evidence.”
In context“The agency launched an undercover operation to infiltrate the smuggling ring, placing several agents in high-risk positions for over a year.”
UsageUsually placed before the noun it describes.
Synonyms - 02 C1 Advanced
n.a person, like a police officer, who works in secret using a fake name.
n.an operative or agent who performs duties while their true identity and motives remain concealed.
Simple“The criminals never suspected that their new driver was actually an undercover.”
In context“The tension in the room spiked when the boss began to suspect there was an undercover among his most trusted lieutenants.”
UsageUsed as a countable noun to refer to the person rather than the action.
Usage undercover agents
“Zwick was targeted by undercover detectives and confessed on March 27, 2024.”
“Rights groups have criticised “sting” operations for using undercover agents to convince suspects to plot attacks.”
From under + cover.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.