I read a book (dystopian, if memory serves) where a certain percentage of the population could communicate through mental telepathy. I think they kept the fact hidden. They referred to the ability as 'lepping'. I've looked everywhere. Anyone remember it? Thanks!
Is it possible you're referred to E.E. Smith's The Galaxy Primes?
The ship was called the Pleiades, and it was Earth’s first starship. It could travel instantaneously to literally anywhere in the universe – but that was just the trouble with it. For there was absolutely no way of predicting where in the infinities of space it would reappear when it winked out of the Solar System, and no way of knowing how to return.
it’s [sic] crew was two men and two women, each a Psionic Prime with mind-powers unparalleled in Earth’s history.
They do use the term "lepping" to refer to telepathy.
"Wait a minute," Lola went on. "There's a funny-looking automobile just coming through the gate. The Press. Three men and two women. To cameras, one walkie-talkie, and two microphones. The photog in the purple shirt is really a sharpie at lepping. Class Three, at least-- possible a Two."
What does not match is that the protagonists are moving from parallel universe to parallel universe, not starting in one, and their talents are not hidden from each other. I believe, from the reviews, that some of the worlds they visit are dystopian.
Found with a Google Books search for telepathy "lepping"
I've found a better match in The Masters of Solitude by Marvin Kaye and Parke Godwin.
In the millennium after a global war, society in the former United States has splintered into groups. The main group in the story, the Coven, live in a pre-industrial Native American lifestyle, but one of growing population and power. Many members have mild telepathic powers, which opens the corridors of power to those capable of "lep". Lep allows the Coven to form larger social groups, but isolation from these groups drives one mad.
The other primary group, The City, retains their former technological lifestyle in the remains of the east coast megapolis. They spend their lives involved in immortal solitary scientific research, meeting rarely and communicating only when their research overlaps. The few thousand remaining City dwellers separate themselves from the "dirty" Coven through the use of the Self Gate, an electronic barrier that drives lesser minds insane. To protect idle attempts to breach it, the City also employs a small mercenary army to act as a police force outside the Gate.
Found with a search for telepathy lepping on regular Google search, which brought up a review in Cryonics Magazine from July 2005.