1
as in clandestine
undertaken or done so as to escape being observed or known by others
an undercover operation to infiltrate the terrorist organization
Synonyms & Similar Words
Relevance
Antonyms & Near Antonyms
as in spy
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
Synonyms & Similar Words
as in underground
Related Words
Dissimilar Words
Example Sentences
Examples are automatically compiled from online sources to
show current usage.
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Recent Examples of undercover
Jason Meisner, Chicago Tribune, 30 Apr. 2026
According to investigators, the weeklong operation targeted individuals who used social media and other online platforms to communicate with undercover detectives posing as minors or guardians of minors.
—Anthony Thompson, USA Today, 30 Apr. 2026
Byron Tau, Chicago Tribune, 30 Aug. 2025
Law enforcement officers working in plain clothes or undercover is nothing new.
—Dana Taylor, USA Today, 22 Aug. 2025
See All Example Sentences for undercover
Adjective
In 1991, Duffy represented a Mercantile Exchange member accused of fraud involving the trading of yen futures, which stemmed from one of the largest and costliest undercover operations the FBI had undertaken.
—Jason Meisner, Chicago Tribune, 30 Apr. 2026
According to investigators, the weeklong operation targeted individuals who used social media and other online platforms to communicate with undercover detectives posing as minors or guardians of minors.
—Anthony Thompson, USA Today, 30 Apr. 2026
Noun
Masks were once largely forbidden on the federal level unless an agent was working undercover, said Michael Bouchard, a former assistant director at the Bureau of Alcohol, Tobacco Firearms and Explosives who retired in 2007.
—Byron Tau, Chicago Tribune, 30 Aug. 2025
Law enforcement officers working in plain clothes or undercover is nothing new.
—Dana Taylor, USA Today, 22 Aug. 2025
See All Example Sentences for undercover
Recent Examples of Synonyms for undercover
Adjective
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Filling out the role of Ilya is Jay Armstrong Johnson; Jimin Moon plays Shane; Ryann Redmond plays a wine-mom narrator who lives for their clandestine love.—
Dan Stahl,
New Yorker,
1 May 2026
-
For those escaping to Philadelphia from regions nearer to Pennsylvania, clandestine travel by small boat or by road was more likely than stowing away on a steamship.—
Jeremy Mennis,
The Conversation,
1 May 2026
Adjective
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First Israeli deployment in an Arab state The covert Israeli deployment of the country’s vaunted Iron Dome missile defense system in the UAE underscored the nations’ deepening ties, an Israeli source familiar with the matter told CNN last week, confirming a report by Axios.—
Tal Shalev,
CNN Money,
1 May 2026
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Paglen traces magickal attempts to mold reality back to midcentury covert operations such as the CIA’s infamous MKUltra program—the one exploring mind control through electroshock therapy, hypnosis, and LSD.—
Louis Bury,
ARTnews.com,
1 May 2026
Noun
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Hong Kong — China’s top spy agency has come out of the shadows to warn that its young people are being duped by foreign forces into shirking hard work and prioritizing their individual emotions at the expense of national development.—
Sylvie Zhuang,
CNN Money,
7 May 2026
-
Lu’s lawyer, John Carman portrayed the case as a mundane bureaucratic blip, not an international spy thriller.—
Michael R. Sisak,
Fortune,
6 May 2026
Adverb
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After writing a book about the social history of street lighting, what brought you underground?—
Christopher Buchanan,
Los Angeles Times,
1 May 2026
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The museum also has restored mining camp buildings and exhibits on the industry's history that don't require a ride underground.—
Zach Wichter,
USA Today,
29 Apr. 2026
Adjective
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Get Ready: Katy Perry Has Released a Sneak Peek of Her New Song And the internet has receipts.—
Mehera Bonner,
Marie Claire,
15 Mar. 2017
Adjective
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From the nearby marina, boat trips to the mangroves (booked through the hotel's diligent concierge) and secret beaches depart regularly.—
Condé Nast,
Condé Nast Traveler,
6 May 2026
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Continue reading … BEHIND CLOSED DOORS — Babysitter’s grim discovery exposes deadly family secret inside luxury home.—
,
FOXNews.com,
6 May 2026
Noun
-
Federal documents show that longtime political operative and Trump ally Roger Stone has since joined DCI's effort, at $50,000 per month.—
Lorcan Lovett,
NPR,
3 May 2026
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The problem is not that every national reporter is a Democratic operative.—
Larry Clifton,
The Orlando Sentinel,
3 May 2026
Adverb
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Haslach also admitted to surreptitiously taking a photo of a minor in a swimsuit by positioning his cellphone under a classroom desk.—
Nick Ferraro,
Twin Cities,
1 May 2026
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Sometimes the batteries on the trackers would run low, and McGovern’s team would need to remove and recharge the devices, before surreptitiously replacing them.—
Ed Caesar,
New Yorker,
30 Apr. 2026
Cite this Entry
“Undercover.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/undercover. Accessed 8 May. 2026.
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