undercover
Americanadjective
-
working or done out of public sight; secret.
an undercover investigation.
- Synonyms:
- hidden, clandestine, covert
-
engaged in spying or securing confidential information.
an undercover agent.
adjective
Etymology
Origin of undercover
Explanation
Undercover means secret or disguised. A police department might send undercover officers dressed as clowns to investigate a corrupt circus. When this adjective was originally used in the mid-19th century, it meant "sheltered beneath something," but after a century or so, it was routinely used to mean "covert or clandestine." If you go undercover, you're doing some kind of secret work, usually inside an organization or group. If the other chess club members want you to be an undercover spy inside the French club, you'll have to brush up on your verb tenses.
Vocabulary lists containing undercover
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
When Conradt didn’t show at the undercover house, NBC and police went to his home in an attempt to serve a search warrant.
From Los Angeles Times • May 27, 2026
The disappearance prompts Jing-nan himself, disguised as a Filipino migrant, to go undercover as a plant employee.
From The Wall Street Journal • May 22, 2026
The caller even provided a “code phrase” that the victim was supposed to say to the alleged undercover officer at their meeting.
From Los Angeles Times • May 13, 2026
In March, an undercover agent contacted one of the participants to ask about the iRobot deal and other trades, pretending to be a securities regulator.
From The Wall Street Journal • May 12, 2026
So White decided that he would be the public face of the investigation, while most of the agents operated undercover.
From "Killers of the Flower Moon" by David Grann
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
