from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The branch of an intelligence service charged with keeping sensitive information from an enemy, deceiving that enemy, preventing subversion and sabotage, and collecting political and military information.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. counterespionage
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. intelligence activities concerned with identifying and counteracting the threat to security posed by hostile intelligence organizations or by individuals engaged in espionage or sabotage or subversion or terrorism
From counter- + intelligence (Wiktionary)