YOLO - Tradução em português

I've being seen this term frequently these days: YOLO. It seems to be something annoying to people who speaks English, like a slang, but actually I think it's not a word and up to now it seems to be a way to sorry for something, but I'm not 100% sure.

Could you help me out?

This is a twitte I just saw and that probably will help you to understand the usage of "Yolo":

"#20PetPeeves People who use "YOLO" as every excuse."

I know that this is not that helpful, but it's not something easy to find in a understandable way

Correct my wrongs please!