The phrase "a perilous thing" is correct and usable in written English.
It can be used to describe something that is dangerous or risky in nature.
Example: "Climbing without proper gear is a perilous thing that can lead to serious injuries."
Alternatives: "a dangerous matter" or "a risky endeavor".
A war that neither side dares to lose and both believe it can win is a perilous thing.
Topicality, like punning, can be a perilous thing, and over the years Mr. Bergeret has contributed his share of groaners.
Had Edward remained in place, he would have been not so much a wet blanket, which is easily managed, as a loose cannon — which, in the late nineteen-thirties, was a perilous thing to be.
This sporting strife "It's a perilous thing to pretend you're a fan of sport when you're not," Nick Clegg said, as he visited the Ageas Bowl cricket ground in Hampshire, making a point of not pretending to be a cricket fan.
By contrast Nick Clegg, the leader of the Lib Dems, when asked if he was keen on cricket, answered that he was not: "It's a perilous thing to pretend you're a fan of a sport when you're not".Mili-BrandEd Miliband was photographed late at night leaving the home of Russell Brand, a comedian who has counselled Britons against voting.
These lines actually appear in the Kirkus review: "Containing elements of the 007 and Jason Bourne sagas, Graham Greene's insular spy novels, William Gibson's cyber thrillers, TV's Burn Notice and Mad magazine's classic Spy vs. Spy comic strip, this book is a narrative hall of mirrors in which nothing and no one are as they seem and emotion is a perilous thing to have".
That said, conditions do change and forward guidance is a pretty perilous thing to do, given the volatility in markets and the microscopic examination of anything the governor says or does.
Taking a boat back to San Marco is a perilous affair.
"The only perilous thing about 'Morgan!' is that it may cause us all to have a bit too much sympathy for beatniks and their childishness in a vicious world," he added.
In this state, probably the most perilous thing most people do is drive on some of the country's oldest and most congested highways.
Because of the nature of what we do, the most perilous thing is usually something you've done to yourself, whether you're going through a gap in a little valley which is maybe a little bit too tight, or the car goes over, or you're driving in very, very heavy rain.
