The noun sleight refers to being able to use your hands with ease, especially when doing a trick. Sleight is often used in the phrase "sleight of hand." If you are a good magician, you can make a coin disappear with sleight of hand.
The noun sleight refers to cunning or cleverness, especially when used to trick or deceive. You can use a sleight of mind to trick yourself into believing that if you eat a box of cookies at dinnertime, it counts as dinner. The word sleight has a long history and comes from the Middle English word sleghth, which also meant "cunning." Back then, people would have pronounced the "gh" — even though today we don't.