Synonyms of undercover

undercover 1 of 3

adjective

ˌən-dər-ˈkə-vər 

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

• clandestine
• underground
• covert
• sneak
• private
• sneaking
• stealth
• secret
• surreptitious
• sneaky
• undisclosed
• behind-the-scenes
• stealthy
• furtive
• underhanded
• hole-and-corner
• backstairs
• underhand
• privy
• confidential
• hush-hush
• off-the-books
• hidden
• hugger-mugger
• classified
• closed-door
• off-the-record
• secreted
• concealed
• restricted
• top secret
• subterranean
• back-channel
• unexposed
• unadvertised

Antonyms & Near Antonyms

• public
• open
• overt
• avowed
• acknowledged
• straightforward
• unrestricted
• unclassified
• obvious
• unconcealed
• evident
• undisguised
• clear
• plain
• aboveboard
• manifest
• patent

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

• covert
• secret
• private
• secretive
• subterranean

Antonyms & Near Antonyms

• overt

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

• spy
• operative
• agent
• mole
• undercover agent
• informer
• secret agent
• emissary
• asset
• spook
• courier
• sleeper
• intelligencer
• double agent
• counterspy
• infiltrator
• stool pigeon
• spymaster
• superspy

undercover

3 of 3

adverb

as in underground

Related Words

• underground
• surreptitiously
• stealthily
• secretively
• covertly
• clandestinely
• furtively
• underhanded
• sneakily
• underhandedly
• underhand
• collusively
• conspiratorially
• offstage
• offscreen
• secretly
• tête-à-tête
• à deux
• inwardly
• sotto voce
• privately
• backstage
• intimately
• confidentially
• in camera

Dissimilar Words

• publicly
• openly

Example Sentences

Recent Examples of undercover

Adjective

The show revolved around Crockett and Tubbs, two undercover detectives infiltrating South Florida’s criminal underworld. — Matt Grobar, Deadline, 13 Oct. 2026

American Nightmare by Kelly McWilliams After surviving the 1906 Atlanta Race Riot, Clark Wendell White joins the NAACP as an undercover operative, using his ability to pass as white to investigate lynchings and infiltrate racist organizations. — Kait Hanson, Southern Living, 13 Oct. 2026

Noun

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

Goode and the Safdies began filming interviews with Tabraue and Crutchfield in 2014, with Josh sporting spy-camera glasses to try to capture Tabraue undercover, but the footage looked like crap. — Marlow Stern, Variety, 6 Aug. 2026