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
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
We sent an undercover researcher, posing as a migrant trying to cross the Channel illegally with his child, into a migrant camp in Dunkirk.
From BBC • May 18, 2026
NHS midwife and certified lactation consultant Olivia Hinge, who reviewed our undercover consultations with self-described sleep experts, says she understands why people offering support with sleep can be so appealing to new mums.
From BBC • May 12, 2026
Piecing together details from Agent Burger’s previous informants as well as from witnesses located by the undercover team, White was able to create a time line.
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.
