L.C.L.Y.
L. C. L. Y. is a Chinese guy or girl who talks too much and acts like they're the best, but they're actually total garbage when they can't do something. It’s like when you’re at a party and someone brags about being a pro gamer, but they can’t even beat you at tic-tac-toe.
My cousin L. C. L. Y. said he could beat me at chess, but he lost in 3 moves.
At the mall, this kid L. C. L. Y. said he could beat me at Fortnite, but I had him dead in 2 minutes.
My teacher called me L. C. L. Y. because I failed my math test and still said I was going to be a mathematician one day.