Short for "brilliant". Mainly used on the internet when someone is too lazy to type out the entire word.
"Whoa dude, that music video was bril."
When something is amazing and spectacular, you say that it's BRIL. When someone has an amazing idea that is really cleaver, you call it BRIL. It's just so bright it's BRIL.
A trendy way of describing all things cleaver.
That art design is just BRIL. Also your idea last week, just bril.