UNDERCOVER Synonyms: 96 Similar and Opposite Words

undercover 1 of 3

adjective

ˌən-dər-ˈkə-vər

Definition of undercover

as in clandestine

undertaken or done so as to escape being observed or known by others an undercover operation to infiltrate the terrorist organization

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Antonyms & Near Antonyms

as in covert

working on missions in which one's objectives, activities, or true identity are not publicly revealed for months she's been an undercover agent pretending to be a drug dealer

Synonyms & Similar Words

Antonyms & Near Antonyms

overt

undercover

2 of 3

a person who tries secretly to obtain information for one country in the territory of another usually unfriendly country within the city was a well-organized fifth column, and these undercovers would make themselves known as soon as the invading forces breached the city limits

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undercover

3 of 3

adverb

as in underground

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of undercover

Adjective

In an unrelated case last year, Stephen Miller asked the bureau to allow agents to go undercover in his Virginia neighborhood's political activist group, several sources with knowledge of the matter told CBS News. — Sarah N. Lynch, CBS News, 8 Oct. 2026 The arrest On Tuesday, FBI agents observed Mohamud leave his residence and meet with an undercover FBI employee in the parking lot of a public park in Richfield, just south of Minneapolis, authorities said during the news conference. — Whitney Wild, CNN Money, 7 Oct. 2026

Noun

Federal prosecutors accused Heidi Beirich, an expert on political extremism and a former director of the nonprofit’s intelligence project, of overseeing payments to informants working undercover in a variety of hate groups. — Jeremy Roebuck, Washington Post, 12 Aug. 2026 Goode and the Safdies began filming interviews with Tabraue and Crutchfield in 2014, with Josh sporting spy-camera glasses to try to capture Tabraue undercover, but the footage looked like crap. — Marlow Stern, Variety, 6 Aug. 2026 See All Example Sentences for undercover

Recent Examples of Synonyms for undercover

Adjective

Bridgers’ tour restricts phones, so the reader’s account had to stand in for the clandestine photo that might otherwise have accompanied the sighting.

— Jeff Ihaza, Rolling Stone, 6 Oct. 2026
The Soviet Union operated an extensive clandestine biological weapons program despite being a party to the Biological Weapons Convention.

— Krutika Kuppalli, STAT, 6 Oct. 2026

Definition of clandestine

Adjective

This year has seen several notable incidents involving both overt and covert threats to undersea infrastructure, including Iranian efforts to impose fees on operators of undersea cables running through the contested Strait of Hormuz.

— Jeremy Hsu, ArsTechnica, 14 Oct. 2026
From hippies to covert racists, psychedelics to cult-like workshop leaders, this is a world where any difference is still scrutinized and looked down on.

— Aramide Tinubu, Variety, 13 Oct. 2026

Definition of covert

Noun

Weeks before the shootdown, the spies allegedly reported on the naval airbase in Key West and were told to transmit Brothers to the Rescue flight data back to the Cuban authorities.

— Liv Caputo Herald, Miami Herald, 19 Oct. 2026
His sixth great-grandfather was a spy in the Revolutionary War.

— Steve Sadin, Chicago Tribune, 18 Oct. 2026

Definition of spy

Adverb

On Monday, fire crews — anticipating a change in wind patterns with the upcoming storm — were working to strengthen containment lines and using drones and thermal imaging cameras to help detect hot spots, including underground, Doran said.

— Los Angeles Times, Los Angeles Times, 19 Oct. 2026
Moreno said the utility company is working to move power lines underground to reduce wildfire risks.

— Brady Halbleib, CBS News, 14 Oct. 2026

Definition of underground

Adjective

Perhaps that doubt is the secret melancholy at the heart of even their most seemingly celebratory songs.

— Philip Sherburne, Pitchfork, 20 Oct. 2026
On Monday, a court granted the US government’s request to deny release of a former OpenAI engineer accused of bugging a top-secret conference room to steal the frontier lab’s secrets.

— Ashley Belanger, ArsTechnica, 19 Oct. 2026

Definition of secret

Noun

His vice president at the nonprofit, a longtime Republican operative, had suggested it, Wilson later testified.

— Christopher Spata, Miami Herald, 17 Oct. 2026
Kenney said the movement also became more professional, building organizations, raising money and drawing in political operatives with campaign and fundraising experience.

— ABC News, ABC News, 17 Oct. 2026

Definition of operative

Adverb

For years, scammers would surreptitiously install skimming devices on card readers at ATMs, gas pumps and corner stores.

— Eli Hager, ProPublica, 13 Oct. 2026
Among the most intriguing possibilities, Brouhard said, is that Gulf nations exporting oil are surreptitiously paying Iran fees in exchange for safe transit through the Strait of Hormuz – even as they’re secured by US military escorts.

— David Goldman, CNN Money, 6 Oct. 2026

Definition of surreptitiously

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“Undercover.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/undercover. Accessed 20 Oct. 2026.

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Synonyms of undercover

adjective

noun

adverb

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