Idiom: Let the Cat out of the Bag Posted on 28th May 201822nd November 2018 by DoubleClick Let the Cat out of the Bag: to share a secret information that shouldn’t be known by others Example: It should be a serious confidential information until someone let the cat out of the bag. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Posted in Idiom and tagged Idiom L.