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
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Recent Examples of undercover
Ian Miller , Alexandra Koch Outkick,
FOXNews.com,
17 June 2026
In 2005, an undercover investigator from the FDA called the farm and was told the milk was safe for human consumption.
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CNN Money,
14 June 2026
Carlos E. Castañeda,
CBS News,
11 Dec. 2025
Four other agents accompanied me, all also operating undercover.
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Martin Suarez,
Rolling Stone,
13 Sep. 2025
See All Example Sentences for undercover
Adjective
This follows a high-profile undercover investigation that revealed at least one MLB team discriminated against a player based on his Catholic faith.
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Ian Miller , Alexandra Koch Outkick,
FOXNews.com,
17 June 2026
In 2005, an undercover investigator from the FDA called the farm and was told the milk was safe for human consumption.
—
CNN Money,
14 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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Some may be announced publicly; others may happen in more clandestine ways.
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But clandestine flows aren’t the biggest factor behind the market calm.
Adjective
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The film follows cybersecurity expert Daniel Kellner (Josh O’Connor), who lifts secret files about the existence of aliens from Wardex, a covert non-government organization that used to employ him.
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The investigation also linked the activity to China based on IP addresses associated with a LinkedIn account and a Gmail account tied to the covert recruitment scheme.
Noun
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For now, a bipartisan housing bill and the renewal of a key spy program have become casualties of those standoffs, and their fate was in limbo as Senate Republicans left for the July 4 recess.
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Oscar-winning actor Gary Oldman, known to fans of AppleTV series Slow Horses as the shambolic, gassy spy Jackson Lamb, will be honored at this year Edinburgh Television Festival with the fest’s lifetime achievement honor, the Golden Icon Award.
Adverb
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Geothermal–which uses hot water underground to generate electricity–is a stable source of baseload power that has bipartisan support.
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The project would relocate the existing Atlantic station underground, and include a mix of underground, aerial and street-level track transit.
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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This house specialty is a whopper of a drink and comes in a goblet filled with the family’s secret blend, which is heavy on Clamato mix.
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The two recently shared a few behind-the-scenes details from their ultra-secret nuptials when Gomez appeared on a March episode of Blanco's podcast.
Noun
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Dunlap launched an insurgent campaign to challenge Golden in 2025, prompting a backlash from the Democratic Congressional Campaign Committee, as well as Democratic lawmakers and operatives who suggested Dunlap could not win the rural, conservative-leaning seat.
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That same year, a Russian helicopter pilot who defected was killed in Spain, with Russian operatives as the prime suspects.
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 27 Jun. 2026.
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