undercover

American  

[uhn-der-kuhv-er, uhn-der-kuhv-] / ˌʌn dərˈkʌv ər, ˈʌn dərˌkʌv- /

adjective

1. working or done out of public sight; secret.

   an undercover investigation.

   Synonyms:

   hidden, clandestine, covert

2. engaged in spying or securing confidential information.

   an undercover agent.

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undercover British  

/ ˌʌndəˈkʌvə /

adjective

1. done or acting in secret

   undercover operations

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Etymology

Origin of undercover

First recorded in 1850–55; under- + cover

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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.

Example Sentences

See Examples For:

undercover

Now, he faces felony charges stemming from the undercover operation.

From Salon ● Oct. 31, 2026

The charges in Utah stem from an undercover operation in which a state investigator opened a Kalshi account under a false name in September and placed 12 wagers on professional and college sports.

From Barron's ● Oct. 29, 2026

“I feel like an undercover superhero, kind of, trying to do everything,” he said.

From The Wall Street Journal ● Oct. 29, 2026

Speaking exclusively to the BBC, Coles lists resilience, bravery and ruthlessness as the qualities needed in a good undercover police officer.

From BBC ● Oct. 21, 2026

I was surprised dude hadn’t already thrown our asses in the back of his undercover cop car.

From "We Were Here" by Matt De La Peña

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Related Words

• covert

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