The phrase "a sly approach" is correct and usable in written English.
It can be used to describe a method or strategy that is cunning or deceitful in nature.
Example: "In negotiations, he often employed a sly approach to gain the upper hand over his opponents."
Alternatives: "a cunning method" or "a devious tactic".
Another questioner tried a sly approach, asking, "What will be your advice to the person who shall replace you as president in less than a year's time?" This sparked a huge surge of laughter.
Their searcher-gadgets locate even well-concealed enemies of state, but their language is beautifully archaic, punctuated with incantations ("Hail the Purge!") and aphorisms ("A sly approach is needed to run state affairs").
This text could indicate that the U.S. wants to do the latter -- a sly approach, as it would be less visible to the public but would likely have the same harmful results.
By all accounts, Mr. Balanchine had a lovably gentle though sly approach for getting what he wanted.
But the show's lightness and quickness are also its strengths: it takes a sly, sidelong approach to the profoundest questions — of establishing love, and how this relates to one's work, of how independence relates to solipsism, and the rising and falling of interest in close friendships.
Many people have not been amused by his sly approach, however.
But nothing could be less drab than Pritchett's sly approach, which, once you're alert to what he's doing, is one of dazzling virtuosity.
Barnard's film, as if nervous of being felled by the straightforward, sinewy thump of Dunbar's writing, ducks and weaves in a series of sly approaches.
Nguyen was born in Vietnam, and raised in America, and embedded in this tightly twisted story of subterfuge is a sly, sophisticated and imaginative approach to understanding the Vietnam War and its aftermath.
The vocals flow and glow with a dreamy, sordid kind of pedestrian sonority rife with a trippy sly sarcasm approaching folly, along with modest colors of umbral revelation.
The narrator, stuck in the usual ambivalent relationship with a guy she doesn't find all that interesting, watches her friendship with Anna, a fellow "long-term temp" who approaches life with a sly, offbeat humor, slide into something more.
