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
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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
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Recent Examples of undercover
Fort Worth Star-Telegram,
23 June 2026
The action film follows cop Brian O'Conner (Walker) going undercover to join the street racing crew led by Dominic Toretto (Diesel).
—
Caroline Blair,
PEOPLE,
23 June 2026
Carlos E. Castañeda,
CBS News,
11 Dec. 2025
Four other agents accompanied me, all also operating undercover.
—
Martin Suarez,
Rolling Stone,
13 Sep. 2025
See All Example Sentences for undercover
Adjective
An undercover officer in an unmarked car spotted the vehicle and began following the suspects.
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Fort Worth Star-Telegram,
23 June 2026
The action film follows cop Brian O'Conner (Walker) going undercover to join the street racing crew led by Dominic Toretto (Diesel).
—
Caroline Blair,
PEOPLE,
23 June 2026
Noun
Le, who was working undercover, was shot while inside his vehicle after responding to one of multiple burglaries at a cannabis business on Embarcadero near Fifth Ave.
—
Carlos E. Castañeda,
CBS News,
11 Dec. 2025
Four other agents accompanied me, all also operating undercover.
—
Martin Suarez,
Rolling Stone,
13 Sep. 2025
See All Example Sentences for undercover
Recent Examples of Synonyms for undercover
Adjective
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That was a concern because other research has indicated the Chinese government has, at times, delayed public disclosure of vulnerabilities submitted to the program so they could later be used in clandestine cyberattacks.
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The screening usually focusses on clandestine hanky-panky, but this season the girls’ irreverence was so abundant that the producers treated them to an unprecedented second viewing night.
Adjective
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To achieve this, Israel employed airstrikes, cyberattacks, interdictions of weapons and covert action to impede Iran’s ability to resupply Hezbollah’s existing arsenal and supply it with more advanced weapons.
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After 1996, when the protease inhibitors were developed, the duty to warn continued to be an important standard when HIV status became more clinically covert.
Noun
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Russia is essentially trying to build a closed, spy-friendly, domestic version of the Internet.
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Brown and Harbour are set to star in and executive produce an upcoming spy drama show from A24 that has received a straight-to-series order at Netflix.
Adverb
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Teams from the United States, France, and Venezuela together freed a father and his son after four days underground.
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Fleming staked much of his campaign on opposition to carbon capture and sequestration, the process for injecting carbon dioxide waste underground to reduce industrial pollution.
Adjective
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Get Ready: Katy Perry Has Released a Sneak Peek of Her New Song And the internet has receipts.
Adjective
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Adding this recipe's not-so-secret ingredient, Bisquick, is a game changer for classic sausage balls.
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Martin Sheen is the Army captain tasked with going on a secret mission to Cambodia to assassinate a special forces officer (Marlon Brando) who's gone rogue and might actually be nuts.
Noun
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In the prosecutor’s statement, the suspect is alleged to have photographed sensitive sites in Israel and then sold the images to an Iranian operative for up to hundreds of dollars.
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Political operatives tied to Florida Power & Light’s parent company were involved in the scandal, and a former Republican state senator was convicted of violating campaign finance laws.
Adverb
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As a group of dancers surrounded her on the B-stage, she was surreptitiously harnessed into a rig that carried her aloft, limp yet belting, into the heavens, or at least into what looked like a UFO hovering over the arena.
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Gray-hat hackers, unlike white-hats, surreptitiously sneak into corporate systems to find security vulnerabilities.
Cite this Entry
“Undercover.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/undercover. Accessed 5 Jul. 2026.
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