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undercover

[uhn-der-kuhv-er, uhn-der-kuhv-] / ˌʌn dərˈkʌv ər, ˈʌn dərˌkʌv- /
ADJECTIVE
secret, spy
Synonyms
STRONGEST
covert
WEAK
clandestine concealed confidential creep furtive hidden hole-and-corner hush-hush incognito intelligence on the Q.T. private stealth stealthy sub-rosa surreptitious under wraps underground underhand underneath
Antonyms
WEAK
known open public

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Meanwhile, Halliday plays Daisy, a recent arrival to the Pearl Girl squad who is really there as an undercover spy for the Gilead’s resistance group, Mayday, under the guidance of June.

From Los Angeles Times • Apr. 8, 2026

Her plot-rich story includes art terrorists, undercover agents, snooty Parisians, sneaky New Yorkers and a one-armed billionaire.

From The Wall Street Journal • Mar. 30, 2026

The police, who are currently concerned about the disappearance of an undercover officer, have their own uses for him.

From Los Angeles Times • Mar. 19, 2026

A male undercover researcher also visited a mini-mart elsewhere in the West Midlands, where we were told vapes were being sold to children.

From BBC • Mar. 19, 2026

Seemed harmless enough, wasn’t even after the reward—we had an undercover approach him with a phony check, he wouldn’t touch it.

From "The Secret History" by Donna Tartt

Vocabulary lists containing undercover

Secret

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