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Synonyms

clandestine

American  
[klan-des-tin] / klænˈdɛs tɪn /

adjective

  1. characterized by, done in, or executed with secrecy or concealment, especially for purposes of subversion or deception; private or surreptitious.

    Their clandestine meetings went undiscovered for two years.

    Synonyms:
    illicit, confidential, underhand, hidden

clandestine British  
/ klænˈdɛstɪn /

adjective

  1. secret and concealed, often for illicit reasons; furtive

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • clandestinely adverb
  • clandestineness noun
  • clandestinity noun
  • unclandestinely adverb

Etymology

Origin of clandestine

First recorded in 1560–70; from Latin clandestīnus, from clamde, clande (unrecorded) (variant of clam “secretly” + -de, adverb particle) + -stīnus (probably after intestīnus “internal”; intestine )

Explanation

Use the adjective clandestine to describe something that is done in secret, like your clandestine attempts to steal your brother's Halloween candy. Clandestine, an adjective imported from Latin, describes a secret, usually illegal activity. Often these things have to do with political and spy organizations. The CIA might run a clandestine operation to infiltrate terrorist organizations. Words with similar meanings include secret; covert, used especially for military matters; undercover, common in espionage; and surreptitious which emphasizes a person's efforts to keep something secret.

Keep Reading on Vocabulary.com

Vocabulary lists containing clandestine

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.

Speakeasies long ago outlived their purpose as clandestine sellers of alcohol, but their appeal has endured.

From The Wall Street Journal • Apr. 9, 2026

They set up clandestine camera monitoring from a public location.

From Slate • Mar. 25, 2026

Sen. Frank Church of Idaho – held extensive hearings that included eye-opening testimony about clandestine U.S. intelligence activities abroad and domestically.

From Salon • Mar. 13, 2026

Indeed, the world’s most high-stakes clandestine cat-and-mouse game is currently taking place in the race for artificial-intelligence supremacy.

From MarketWatch • Feb. 28, 2026

As he squeezed in beside her and felt her whole left side pressed against his right, he had to take a clandestine deep breath—she smelled like fruit and flowers—and force himself to focus.

From "Dear Martin" by Nic Stone