let slip something

let (something) slip

To accidentally or inadvertently reveal some secret or important piece of information. I can't believe your sister let news of our engagement slip in front of your parents! The agent, under the influence of a powerful truth serum, let slip the names of other operatives working covertly in the area.
See also: let, slip

let ˈslip something

give somebody information that is supposed to be secret: She tried not to let slip what she knew.I happened to let it slip that he had given me $2 000 for the car.
See also: let, slip, something
References in classic literature ?
The good man has no doubt let slip something on that subject also, though mother would deny it: 'I shall refuse,' says she.
But the Labour leader let slip something he probably didn't mean to say, as he answered questions following the launch of his party's General Election manifesto.
The female officer, codenamed Sonia, chatted up the loner in the hope he would let slip something incriminating.
But Kenny Dalglish did let slip something significant in the aftermath.
Someone may let slip something you have told them in confidence.
On the funeral of the 26-year-old, who in recent months had pitched himself against Mehsud, his brother Misabhuddin vowed to reporters that he would take revenge against Mehsud, he also let slip something else.
However, if you get too caught up in the moment, it can lead to a red face if you let slip something that would be better kept a secret.
During an interview with Simon Davies at Spurs on Friday, the Welsh international let slip something that might just constitute news to your average Cardiff City fan (if there is such a being).
When it comes to bioterrorism and its insidious infectious diseases, we've let slip something that was once pretty good.