"sly strategy" is correct and usable in written English.
You can use it to refer to a strategy that has been carefully planned with the intention of outwitting someone or achieving a particular outcome. For example: "The politician's sly strategy of attacking his opponent's record while refusing to answer questions about his own policies played strongly with the electorate."
Meantime, I will happily pilot my own car, slowing to a crawl to irritate the honker behind me, shouting at morons and blockheads who don't use their signals, and using sly strategies to edge out the other guy for the last parking spot.
But Baker, bless his obsessive-compulsive heart, doesn't seem to mind: one of his sliest strategies always has been to present himself as a hand-wringing head case with an off-the-charts I.Q.
"The more you take credit, the less able you are to do something the next time," said Mr. Sturz, 69, who is regarded as much for his penetrating social vision as for his sly-fox strategies for applying bricks and mortar to his ideas.
Was this nasty non-story an aberration by the Standard or the start of a lockstep march to polling day with Goldsmith's sly "red scare" campaign strategy?
The children can learn better strategies for manipulative, sly behavior from each other.
One of Mr. Schickele's signature strategies is the sly interweaving of musical references into a single pastiche.
The writers would have hailed Carroll as "sly" and "wily" and "crafty" and "shrewd" if his strategy had worked: "ingenious," even -- maybe the philosopher king reigning over a new NFL dynasty that de-throned Sauron-like Belichick.
Klara displays a complex mix of pique, sly precocity, emerging but still half-hearted conscience, passivity as an avoidance strategy, inability to challenge an adult's robust narrative, muddled memory and genuine confusion that seems altogether convincing.
Doubling down on his belief in building a sustainable and independent business, Aggarwal made a sly dig at Uber in suggesting that the U.S. company is preoccupied with short-term strategies in India.
Experts in Go strategy report that it (I initially wrote "he" …) played in non‑obvious ways, making unusual, sly and even bizarre moves that only belatedly revealed themselves as tactically worthwhile.
