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

In exchange, one of the agents asked Lumumba to move the city’s deadline for the hotel project from April 30 to April 10 or 15, giving the undercover FBI agents an advantage over other developers. — Natalie Neysa Alund, USA Today, 6 July 2026

On June 19, police sent an undercover officer in the hotel, where he was greeted by a woman in a nightgown. — Nate Gartrell, Mercury News, 4 July 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