- to reveal the true identity
- to put a damper on someone's plan to conceal something
- to reveal a secret
- inadvertently give away one's secret identity.
- The custom's officer recognised the man from a wanted poster and blew his cover right out.
- She did not intend to blow his cover but then her habit of blabbering did not help.
- I bought some gold under the pretext of going shopping for clothes but my toddle blew my cover in front of my in-laws.
- The income tax department as blown the cover off many tax evaders in the last three months.
- The new government regulation is intended to blow the cover of the people who hoard money.
- The lawyer blew the criminal's cover in quite an interesting manner. Luckily I got to witness it all.
- The multilevel marketing company's cover was blown when the journalist interviewed its top management.
- Although he has been a spy for many years, his cover was blown in this operation and hence he got caught.
- The burglar came to the marriage in a gentleman's dress and hoped no one would blow his cover.
The phrase is speculated to originate in troubled times and war zones where a cover being blown could literally result into life and death situations. The popularity of the phrase comes from Hollywood spy movies.