undercover 1 of 3

adjective

ˌən-dər-ˈkə-vər How to pronounce undercover (audio)
Definition of undercovernext
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
2
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

undercover

2 of 3

noun

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

undercover

3 of 3

adverb

as in underground

Related Words

Dissimilar Words

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
The final twist of the episode showed that OA’s later job offer from Anna was part of a larger undercover plan involving Maggie and Isobel Castille (Alana De La Garza), the special agent in charge of the New York field office. — Emily Krauser, PEOPLE, 29 Aug. 2026 Link testified over two days about his undercover role, receiving a break at sentencing for his own tax conviction. — Jason Meisner, Chicago Tribune, 28 Aug. 2026
Noun
The Agency‘s second season will continue following Martian, a CIA agent living undercover in his own life. — Rosy Cordero, Deadline, 19 May 2026 Meanwhile, Chee goes further undercover. — Jordan Hoffman, Entertainment Weekly, 16 Mar. 2026 See All Example Sentences for undercover
Recent Examples of Synonyms for undercover
  1. clandestine
  2. covert
  3. spy
  4. underground
  5. private
  6. secret
  7. operative
  8. surreptitiously
Adjective
  • The clandestine manner in which LG monitors were installing ad-pushing software onto third-party devices, however, remains seriously concerning.
    — Scharon Harding, ArsTechnica, 24 Aug. 2026
  • The clandestine transits have changed the game for the Middle Eastern oil industry.
    — David Goldman, CNN Money, 22 Aug. 2026
Definition of clandestine
Adjective
  • Psyops can be overt or covert, but they’re designed with a clear objective, said Jan Goldman, a professor of intelligence and security studies at The Citadel who has also worked on psyops.
    — Harmeet Kaur, CNN Money, 27 Aug. 2026
  • In a recent presentation, OpenAI researchers described how AI agents used a covert message board to plan their next moves.
    — Alex Heath, Time, 26 Aug. 2026
Definition of covert
Noun
  • Yet the Department of Military Counterintelligence—formally responsible for detecting foreign spies within the armed forces—has also been involved in many cases, reflecting the growing dependence of Russian industries on military contracts.
    — Andrei Soldatov, Foreign Affairs, 31 Aug. 2026
  • The Bourne Identity Teens who enjoy action movies and spy capers will be all about the first film in the Bourne movie series, which came out in 2002.
    — Kara Nesvig, Parents, 29 Aug. 2026
Definition of spy
Adverb
  • The design is particularly important for a project where the machines will eventually have to be dismantled deep underground after completing their work.
    — Sujita Sinha, Interesting Engineering, 31 Aug. 2026
  • While some of these latrines connected to pipes that moved waste underground, very few drained into Ancient Rome’s sewer system.
    — Andrew Coletti, Popular Science, 27 Aug. 2026
Definition of underground
Adjective
  • Some are worried about the legal implications of handling such large quantities of previously private game builds as well.
    — Kyle Orland, ArsTechnica, 30 Aug. 2026
  • In the village of Bilbasovka in eastern Ukraine, a 13-year-old child and an adult died after Russian troops dropped bombs on private houses Sunday, according to local official Vadim Lyakh.
    — ABC News, ABC News, 30 Aug. 2026
Definition of private
Adjective
  • From a secret Las Vegas elopement in January that cost the couple only $799, as Windey told Cosmopolitan, to an April courthouse ceremony.
    — Mariah Alanskas, PEOPLE, 2 Sep. 2026
  • Niemiller and his team have named the new species Demogorgonichthys arcanus, a wink to the otherworldly creature that emerged in a secret federal lab in the Netflix series Stranger Things.
    — Elizabeth Anne Brown, Scientific American, 2 Sep. 2026
Definition of secret
Noun
  • Filming has now begun on location in Malta, with Winstone starring as Alan ‘Razor’ Sharp, a former SAS operative haunted by a botched mission in the 1990s that left his reputation in tatters and his best friend dead.
    — Jesse Whittock, Deadline, 1 Sep. 2026
  • The six-part series sees Winstone play Razor, a former SAS operative haunted by a botched mission in the ‘90s that left his reputation in tatters and his best friend dead.
    — Alex Ritman, Variety, 1 Sep. 2026
Definition of operative
Adverb
  • These malicious apps can be surreptitiously installed by remote attackers even when the devices are positioned behind a router.
    — Dan Goodin, ArsTechnica, 31 Aug. 2026
  • For every song ingested into these LLMs, ALL of the creative elements that went into the track have been surreptitiously appropriated.
    — David Barber, HollywoodReporter, 31 Aug. 2026
Definition of surreptitiously

Browse Nearby Words

undercoats
undercover
undercover agent
See all Nearby Words

Cite this Entry

“Undercover.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/undercover. Accessed 5 Sep. 2026.

Copy Citation
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

A List of Most Commonly Confused Words

Why do we use apostrophes to show possession?

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?
See More

Popular in Wordplay

See More

The Longest Long Words List

Stay Woke

Ye Olde Nincompoop: Old-Fashioned Words for 'Stupid'

14 Phobias You Probably Haven't Heard Of

The Words of the Week - Sept. 4
See More

Popular

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

The Longest Long Words List

Stay Woke
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
anagrams on a chalk board
Word Builder Quiz Vol. 2 Pick the letter that when added to a word will ma...
See All