Blow someone’s cover

To blow someone’s cover is an idiom that has been in use for about one hundred years. An idiom is a word, group of words or phrase that has a figurative meaning that is not easily deduced from its literal definition. Common idioms are words and phrases used in the English language in order to convey a concise idea, and are often spoken or are considered informal or conversational. An idiom can illustrate emotion more quickly than a phrase that has a literal meaning, even when the origin of the idiomatic expression is lost. Many English as a Second Language students do not understand idiomatic expressions, as they attempt to translate them word for word, which yields only the literal meaning. In addition to learning vocabulary and grammar, one must understand the figurative language of idiomatic phrases in order to know English like a native speaker. We will examine the definition of the phrase blow someone’s cover, where it came from and some examples of its use in sentences.

To blow someone’s cover means to expose someone’s true identity, to expose someone’s true purpose, to reveal someone’s true, hidden motives. The term blow someone’s cover is related to the word undercover, which means to operate in secret, usually with a fake identity. Policemen may work undercover in order to infiltrate criminal organizations. Journalists may work undercover in order to expose corruption. Spies may work undercover in order to gather intelligence. If the true identity of such a person is exposed, then someone has blown their cover. This may result in someone being put in danger, or it may simply foil that person’s plans. Sometimes the term blow someone’s cover is used in a humorous way, to mean spoiling a surprise. Related terms are blows someone’s cover, blew someone’s cover, has blown someone’s cover, blowing someone’s cover.


“She escorted me to a silver trailer and knocked on the door, whereupon two stylists answered and yanked me inside as if I were a spy about to blow my cover.” (The Minneapolis Star Tribune)

Police are closing in on a burglary suspect who broke into a home in south Arlington last week and blew his cover when he tried to deactivate the home surveillance video camera. (The Fort Worth Star Telegram)

The enemy might spot your agents, seemingly by chance, blowing your cover and exposing your team to an inevitably dismal firefight. (The Guardian)

He admitted it was the first moment he had a “physical reaction” to something a target said, and he “saw red” and worried he had blown his cover. (The Sun)

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