Apparently Lady Rionne had been conducting a clandestine correspondence with her home Domain.

Messina Denaro used the pseudonym "Alessio" in his clandestine correspondence with former Mafia boss Provenzano.

Walsingham instructed Paulet to open, read and pass to Mary unsealed any letters that she received, and to block any potential route for clandestine correspondence.

Instead, they embarked on a clandestine correspondence.

Such was the man with whom I suspected you to maintain a clandestine correspondence.

You engaged in a clandestine correspondence with my Sister, whose affections. . . .' 'Have ever been, and still are mine.

There was also clandestine correspondence from big-name composers like George Gershwin who did not want the world to know that they were still taking music lessons.

Angelina, you have been carrying on a clandestine correspondence with this . . . love-starved puppy.

Whether the torments of absence were softened by a clandestine correspondence, let us not inquire.

He ought really to know that his servants are carrying on clandestine correspondences, shouldn't he?