off the record

off the record (something said with the intention of remaining private) — не для публики; не для печати,не для прессы, не для протокола; не подлежит оглашению, конфиденциально, закрыто (об информации); неофициальным путем

If you say something off the record , you don't want it in the public record, or reported in the media. When you say:

I’m going to tell you this off the record ,

you mean something like:
I’ll tell you, but you can’t use my name.
I’ll tell you, but you can’t use it against me.
I’ll tell you, but I’ll deny it if you tell anybody.
(english-idioms-and-expressions.com)
Examples:

... Keep my comments off the record.
...She made it clear that her comments were strictly off the record.— Она дала понять, что её комментарии строго конфиденциальны.
...The minister has refused to speak to reporters since something he said off the record was reported in a newspaper.
(englishclub.com)
...Off the record, I do think the coach has done me a disservice by benching me.

Usage notes:
If used to modify a noun or a noun phrase, hyphens must be added, as in "off-the-record comments" .