He was suspected of being active in a clandestine movement.

Money laundering is, by definition, a clandestine enterprise.

This birch grove is a very romantic spot for a clandestine rendezvous.

Ferhat Mehenni is said to have held many clandestine meetings with Moroccan officials.

“And now,” he said, after a moment's consideration, “it is fit I should speak to Sir William Ashton; he must know of our engagement. Ravenswood must not seem to dwell under his roof to solicit clandestinely the affections of his daughter.”

Sami and Layla began a clandestine relationship.