private matter

See: secret
References in classic literature ?
I give you my hand upon that; and I thank you again and again; and I will just add one little word, Utterson, that I'm sure you'll take in good part: this is a private matter, and I beg of you to let it sleep.
My first business is a private matter with these gentlemen.
I answered that it had ceased to be a private matter, but had become a public one, since the ruined coronet was national property.
The excuse he gave for his appearance was that he had come to consult the chief of the dervishes on a private matter of great importance.
An engagement--horrid word in the first place--is a private matter, and should be treated as such.
The Alta-Pacific had suggested that his resignation be kept a private matter, and then had privily informed the newspapers.
He was sent for on my suggestion that I was willing to pay his days wages to his foreman for the privilege of asking him a few questions on a private matter.
I got to talking some pretty private matters presently, and Harris became nervous; so he nudged me and said:
And I must plainly say ye drove a fool's bargain when ye let a man like the sailor-man so far forward in your private matters.
I was forced to come into the City upon some little private matters of my own, and couldn't pass the corner of the street without looking in, but upon my soul I didn't expect to find you.
The agitation thrilling through the country and army in consequence of this news was so great, that private matters were little heeded: and hence probably George Osborne, just gazetted to his company, busy with preparations for the march, which must come inevitably, and panting for further promotion--was not so much affected by other incidents which would have interested him at a more quiet period.
Incidentally, I may tell you that we are doing the reverse of what you very justly blame, and that we are endeavouring to prevent anything like public exposure of private matters which must necessarily follow when once the case is fairly in the hands of the official police.