In espionage, agents under non-official cover (NOC) are operatives who assume covert roles in organizations without ties to the government for which they work. Such agents or operatives are typically abbreviated in espionage lingo as a NOC (pronounced "knock").
权威例句
1.
New identities are usually reserved for officers under "non-official cover, " where they are generally assuming identities that are totally dissociated with the U.S. government.