not for publication
Not to be shared, spread around, or talked about with anyone else. Look, this isn't for publication, but I heard there's going to be a round of layoffs next month. Jen and David are getting a divorce! No one else knows yet, so that isn't for publication.
not for publication
not to be talked about openly; secret. Please tell no one about this. It's not for publication. This report is not for publication, so keep it to yourself.