Slight and sleight sound the same, but things that are slight are little and light, and sleight means slyness or sneakiness.

Slight is usually an adjective that describes things that are small, flimsy, or insignificant, like a slight drop in the temperature. If a book critic refers to a novel as slight, she could mean either that it’s short or that it’s trivial in its concerns. As a noun, slight means “a snub or insult,” and you can also use this word as a verb when someone does the snubbing or insulting. Check it out:

The slight decline registered Tuesday followed five weeks of steadily rising numbers.
(Washington Post)

Repeatedly throughout his career, Jordan used slights against his greatness as motivation to obliterate all before him.  (The Guardian)

I feel slighted by their thoughtlessness and irritated that he doesn’t seem to care. (Slate)

Sleight, on the other hand, means being crafty and clever, often by being quick-handed. It’s most commonly used in the phrase “sleight of hand.” A magician uses sleight of hand to pull a quarter from behind your ear. Tada! Here are some more examples:
“I was learning to do sleight of hand by amazing magicians, and I demonstrated magic over-the-counter, like I am now again doing,” (Washington Post)

The show contains a slew of card tricks, but the real sleight of hand is the transformation of digital into theatrical space. (Los Angeles Times)

Don’t confuse “sleight of hand” with being slight of hand — which is just a strange way to say that your hands are really small! To remember the distinction between these homophones, you can remind yourself that a tricky magician snuck an “e” into sleight.