Learn English idioms with meanings and examples

🌎Region: International 📊Difficulty Level:intermediate

blow your cover

To reveal your secret identity, role, or hidden plan—often by saying or doing something that exposes you.

From espionage and undercover work: a “cover” is a false identity or disguise. If you “blow” it, you destroy that protection and get exposed.

Suggests an undercover role or secret being exposed, often through a slip-up. Fairly informal; used literally for spies/police and figuratively for surprises or hidden motives.

  • Don’t mention the project in front of them—you’ll blow your cover.
  • He blew his cover by using the wrong name at the checkpoint.
  • If you ask too many questions, you might blow your cover as a new employee.
  • She tried to act casual, but her accent almost blew her cover.
  • We can’t park outside the building again; it could blow our cover.

Possessive varies (blow my/your/his cover). Verb inflects (blew, blown). Often appears as “blow someone’s cover” or passive “have your cover blown.”

  • give yourself away
  • reveal yourself
  • expose yourself
  • blow your disguise
  • tip your hand
  • keep your cover
  • stay undercover
  • keep it under wraps
  • maintain secrecy