Definition of let the cat out of the bag in US English:

let the cat out of the bag

phrase

informal
  • Reveal a secret carelessly or by mistake.

    • ‘Apparently, my relative let the cat out of the bag by letting villagers know that he is the father of the child.’
    • ‘He said: ‘What is clear is what has happened in Scarborough has let the cat out of the bag and is going to result in rapid changes.’’
    • ‘Our families did a fantastic job in not letting the cat out of the bag, although there were times when I panicked that something might slip out.’
    • ‘The rather inappropriately named Defence Minister let the cat out of the bag by admitting that there isn't really a threat after all.’
    • ‘Two such academics were so upset by the broadcast they injudiciously let the cat out of the bag completely.’
    • ‘Apologies to all your eight-year-old readers for letting the cat out of the bag!’
    • ‘Just as he should be celebrating a new poll that puts the Tories only a point behind Labour, the deputy chairman has resigned after letting the cat out of the bag.’
    • ‘It isn't letting the cat out of the bag to suggest you should expect an unconventional evening's entertainment this time, although to say much more would be to spoil the surprise.’
    • ‘Gavin Anderson apologises to those in the know for letting the cat out of the bag about this secret haven’
    • ‘So let the cat out of the bag: admit that what you're really up to is a satire on the state of arts funding.’