Dictionary.com
Thesaurus.com

counterintelligence

American  
[koun-ter-in-tel-i-juhns] / ˌkaʊn tər ɪnˈtɛl ɪ dʒəns /

noun

  1. the activity of an intelligence service employed in thwarting the efforts of an enemy's intelligence agents to gather information or commit sabotage. CI

  2. an organization engaged in counterintelligence. CI


counterintelligence British  
/ ˌkaʊntərɪnˈtɛlɪdʒəns /

noun

  1. activities designed to frustrate enemy espionage

  2. intelligence collected about enemy espionage

"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

Etymology

Origin of counterintelligence

First recorded in 1935–40; counter- + intelligence

Explanation

Information and activity that helps to expose or eliminate spying or terrorist threats is counterintelligence. One of the things the CIA is responsible for is counterintelligence. Governments spy on each other, and the action of spying is called intelligence or espionage. When a country works to oppose or uncover spying, it's counterintelligence, or counterespionage. In the United States, both the CIA and the FBI have counterintelligence units. The word has been used since 1940, from counter, "against," and intelligence, from the Latin intelligentia, "power of discerning." The sense of intelligence as "secret information from spies" dates from the 16th century.

Keep Reading on Vocabulary.com

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.

See Examples For:

“Drones are just more effective and cost less,” said Kovalskiy, who is part of a military counterintelligence division of the Security Service of Ukraine, or SBU.

From The Wall Street Journal May 14, 2026

The number of FBI employees working in counterterrorism and counterintelligence continues to fall.

From Slate Apr. 21, 2026

It calls for a mandatory registration system for foreign agents -- such as individuals and corporations lobbying within Japan on behalf of other governments -- as part of counterintelligence measures.

From Barron's Feb. 27, 2026

The verdict marked the Justice Department’s first conviction on AI-related economic espionage charges, according to a statement from Roman Rozhavsky, assistant director of the FBI’s counterintelligence and espionage division.

From Los Angeles Times Jan. 30, 2026

“It means that in addition to your studies at Kinloch,” he said, “you’ll receive instruction in espionage, counterintelligence, self-defense, code-breaking, and other assorted goodies.”

From "City Spies" by James Ponti

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training