"clandestine matters" is a correct and usable phrase in written English.
It is often used to describe activities that are done in secret or under a layer of secrecy. For example, "The spies gathered in a dark alley to discuss clandestine matters".
He brought a clandestine thing out into the open".
Abortion was not always a clandestine affair in Chile.
He had a history of deceiving the authorities about security matters and clandestine contact with foreign scientists.
"The problem with clandestine abortions in Chile is a matter of equality," says Dr. Beatriz Sagaldo, a GP working for the Department of Public Health at the University of Valparaíso.
"Still, Mr. Cruz, your long and, I regret to say, clandestine treatment of this dual-citizenship matter raises questions that I'm sure you'll wish to address, if only to put to rest any lingering concerns about America's safety and security.
Then there is the matter of the Mayor's clandestine process for selecting Klein's successor.
But that does not matter for this show, for the clandestine quality of the space suits the work.
The clandestine excuses are: it's a private family matter; people should not air family dirty laundry to the public (no matter how bloody it is); there are two sides to every story so we don't get involved and pick sides (even though only person is being battered); it happens all of the time - people work it out themselves.
This did not matter much a decade ago, when the main trade was the clandestine shipment of arms to fuel civil wars.
Not the least of these is the chance to be feminine again in matters of dress and appearance, and to pursue those ideals without resorting to clandestine tactics.
