between you, (and) me, and the lamppost
In complete confidence between the speaker and the listener, as of a forthcoming secret or rumor. Now, this is between you, me, and the lamppost, but I'm thinking about filing for divorce. Between you and me and the lamppost, I hear that they're going to lay off half the staff by the end of the week. I overheard the boss talking to her secretary last night and—just between you, me, and the lamppost—she's giving the promotion to George after all.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.