The letter didn't offer up the jewels, only shadowy suggestions about their disappearance, claiming that [heiress, Carolyn] Skelly, in a surreptitious trading of parcels with "a man in an ankle-length tweed overcoat," had left a bag full of jewelry on the floor at J.F.K. — Mark Seal , Vanity Fair ,

In the early evening as we gathered in the lobby beneath mounted elk heads and bear skins, the lights of the chandelier flickered mysteriously. But the teacher and I both spied the surreptitious action of the desk clerk, whose sheepish smile acknowledged that one brief hotel mystery had been solved. Other signs of pranking there included a "ghost" photo (displayed in a lobby album) that the clerk confided to me was staged, and some pennies, placed on the back of a men's room toilet, that from time to time would secretly become rearranged to form messages—like the word "why?" that I encountered. — Joe Nickell , Skeptical Inquirer ,

The next week offered [FBI agent] Wiser the opportunity he had been waiting for. Ames was leaving the country, going to Ankara for a weeklong international conference on drugs. Wiser went to Bryant for permission to run a … surreptitious search of Ames' garbage. But the chief was dead set against it. — Tim Weiner et al. , Rolling Stone ,

She had a surreptitious relationship with her employee.

a private investigator adept at taking surreptitious pictures of adulterous couples