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