slay

Meaning

1. To do something extremely well or look extremely good.
2. (interjection) Said to praise someone for doing exactly that.

“That outfit? Slay.”

Where it came from

The modern sense comes from Black and Latino ballroom and drag culture, where it praised a flawless performance or look. Black Twitter and gay Twitter carried it into wider internet slang through the 2010s, and mainstream platforms adopted it by decade’s end.