undercover

1 of 3

adjective

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

undercover

2 of 3

noun

: a person engaged in undercover activity : spy

under cover

3 of 3

phrase

1

: in an envelope or wrapper

2

: under concealment : in secret

Synonyms of undercover

Adjective

• clandestine
• underground
• covert
• sneak
• private

Noun

• spy
• operative
• agent

Examples of undercover 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

Adjective

The growing fear in the community and rumors of undercover ICE agents in churches and church parking lots in other areas of the country has lead pastors to make major changes to their programming. — Lauren Costantino september 19, Miami Herald, 19 Sep. 2026

Murphy’s gang weren’t really outlaws to begin with — he was imprisoned for defending his daughter from some undercover cops, while Singh (Avi Nash) was arrested for his associations with socialism. — Katie Walsh, Los Angeles Times, 18 Sep. 2026

Noun

Steinem spent 11 days working undercover as a bunny in Manhattan's Playboy Club and documenting her experience. — Jennifer Hassan, USA Today, 3 Sep. 2026

Federal prosecutors accused Heidi Beirich, an expert on political extremism and a former director of the nonprofit’s intelligence project, of overseeing payments to informants working undercover in a variety of hate groups. — Jeremy Roebuck, Washington Post, 12 Aug. 2026

Phrase

The website became the primary go-to for consumers looking for country news, and Morris remained there into his mid-80s, until 2020, when, under cover of COVID, MTV Networks began to dismantle its once-flourishing news sites. — Chris Willman, Variety, 20 Sep. 2026

Vols fans revolted, burning couches and rioting on campus, while Kiffin left under cover of darkness. — Austin Perry Outkick, FOXNews.com, 18 Sep. 2026

Word History

First Known Use

Adjective

1920, in the meaning defined above

Noun

1962, in the meaning defined above

Rhymes for undercover

• rediscover
• cover
• hover
• plover
• discover
• hardcover
• recover
• thereover
• uncover

Kids Definition

undercover

adjective

un·​der·​cov·​er

-ˌkəv-ər

: acting or performed in secret

an undercover scheme

especially : employed or engaged in spying or secret investigation

an undercover agent

undercover adverb