Slay can mean “to kill a person or animal,” “to make someone laugh,” “to have sex with someone,” or “to do something spectacularly well,” especially when it comes to fashion, artistic performance, or self-confidence. Slay spread in the intersectional worlds of gay culture, fashion, and the drag scene. It was heavily featured in 1991 in the influential New York drag documentary Paris Is Burning. When RuPaul’s Drag Race brought drag culture into millions of living rooms starting in 2009, slay got a massive signal boost. In 2016, Beyoncé took slay mainstream. She commanded her ladies to get in formation and slay.

Source: Dictionary.com