clandestine

adjective

clan·​des·​tine klan-ˈde-stən 

also -ˌstīn

or -ˌstēn

or ˈklan-də-

: marked by, held in, or conducted with secrecy : surreptitious

a clandestine love affair

clandestinely adverb

clandestineness noun

clandestinity

ˌklan-də-ˈsti-nə-tē 

-de-ˈsti-

noun

Did you know?

Psst!—if your first instinct, upon being asked what you’ve been up to, is to clam up, your querier may suspect you’ve been involved in some clandestine activities. Clandestine often substitutes for secret and covert, and it is commonly applied to actions that involve secrecy maintained for an evil, illicit, or unauthorized purpose, as in "clandestine activities pursued under cover of night." It comes to English by way of Middle French, from the Latin word clandestinus, which is itself from the Latin adverb clam, meaning "secretly." Note that this clam is not the ancestor of the English word clam, despite how tightly sealed and thus secretive the bivalves may seem.

Synonyms of clandestine

• undercover
• covert
• underground
• sneak
• private
• surreptitious

Choose the Right Synonym for clandestine

secret, covert, stealthy, furtive, clandestine, surreptitious, underhanded mean done without attracting observation.

secret implies concealment on any grounds for any motive.

met at a secret location

covert stresses the fact of not being open or declared.

covert intelligence operations

stealthy suggests taking pains to avoid being seen or heard especially in some misdoing.

the stealthy step of a burglar

furtive implies a sly or cautious stealthiness.

lovers exchanging furtive glances

clandestine implies secrecy usually for an evil, illicit, or unauthorized purpose and often emphasizes the fear of being discovered.

a clandestine meeting of conspirators

surreptitious applies to action or behavior done secretly often with skillful avoidance of detection and in violation of custom, law, or authority.

the surreptitious stockpiling of weapons

underhanded stresses fraud or deception.

an underhanded trick

Examples of clandestine in a Sentence

The clandestine meetings, the passing back and forth of messages between Lodge and the plotters, the coaxing along of the generals, all had the emotional lift of a strong amphetamine. —Neil Sheehan, A Bright Shining Lie, 1988

The CIA's great innovation has been to concentrate in peacetime on 'covert action'—that is, the use of clandestine means to challenge policies and regimes in other countries. —Arthur M. Schlesinger, Jr., The Cycles of American History, 1986

And Pym was in London for a conference—no, he wasn't, he was attending a three-day course on the latest methods of clandestine communication in a beastly little training house off Smith Square. —John le Carré, A Perfect Spy, 1986

I took a clandestine peek at the price tag on the diamond necklace.

Recent Examples on the Web

The Pozo de Vargas is considered the largest clandestine mass grave of Argentina’s last dictatorship with the remains of 149 people recovered from the site. —ABC News, 22 Mar. 2026

Five Mexican nationals were indicted on federal drug trafficking and weapons charges this week after authorities discovered a clandestine methamphetamine lab in Northern California, leading to the seizure of nearly 3,000 pounds of the drug, officials said. —Greg Wehner, FOXNews.com, 20 Mar. 2026

For the three people left in the world who remain uninitiated, breakout stars Hudson Williams and Connor Storrie play Shane Hudson and Ilya Rozanov, two rival hockey captains who fall in love over the course of a decade of yearning and clandestine hookups. —Emily Tannenbaum, Glamour, 19 Mar. 2026

Adult Swim viewers became part of a late-night collective bearing witness to clandestine artifacts anyone who went to bed at a reasonable hour would only hear about from their bleary-eyed friends. —Eric Vilas-Boas, Vulture, 18 Mar. 2026

Word History

Etymology

Middle French or Latin; Middle French clandestin, from Latin clandestinus, from clam secretly; akin to Latin celare to hide — more at hell

First Known Use

circa 1528, in the meaning defined above

Rhymes for clandestine

• intestine
• progestin

Podcast

Get Word of the Day delivered to your inbox!

Kids Definition

clandestine

adjective

clan·​des·​tine klan-ˈdes-tən 

: done in secret

a clandestine meeting

clandestinely adverb