under cover
1 of 3phrase
1
: in an envelope or wrapper
2
: under concealment : in secret
un·der·cov·er
ˌən-dər-ˈkə-vər 
: acting or executed in secret
specifically
: employed or engaged in spying or secret investigation
an undercover agent
undercover
adverb
Examples of under cover in a Sentence
Adjective
an undercover operation to infiltrate the terrorist organization
for months she's been an undercover agent pretending to be a drug dealer
Noun
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
Recent Examples on the Web
Kevin Jacobsen, Entertainment Weekly, 31 Jan. 2026
Eriksen was also discovered to have been chatting online with an undercover law enforcement agent who was posing as the mother of an 8-year-old daughter.
—Chris Ramirez, jsonline.com, 30 Jan. 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 under cover
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Adjective
Joining George in his fight to stop the slasher are a particularly suspicious student (Ian Sera) and a famous tennis pro (Lynda Day George) who, bored with the celebrity touring circuit, decides to join up as an undercover detective.
—Kevin Jacobsen, Entertainment Weekly, 31 Jan. 2026
Eriksen was also discovered to have been chatting online with an undercover law enforcement agent who was posing as the mother of an 8-year-old daughter.
—Chris Ramirez, jsonline.com, 30 Jan. 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 under cover
Cite this Entry
“Under cover.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/under%20cover. Accessed 1 Feb. 2026.
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