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.
Steve Coogan is terrific in a rare dramatic role, as is Tom Burke as cop teetering on the edge as he falls dangerously deep into his undercover persona.
From MarketWatch • May 31, 2026
Confronted on the phone by our undercover researcher, Ahmad denied any involvement in people smuggling.
From BBC • May 18, 2026
Pedro Pascal took his “Star Wars” character to the streets on Saturday, going undercover as the Mandalorian to surprise Disneyland guests aboard the Millennium Falcon: Smuggler’s Run attraction.
From Los Angeles Times • May 18, 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
“What did happen at that meeting with the undercover flatfoot?”
From "The Milagro Beanfield War" by John Nichols
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.
