Although it's now used as another word for cool, it literally means something that strucks awe. Something so amazing, one is in awe seeing it. But like I said, nowadays it's used just like cool.
You. You, there, sitting there looking at the screen of your laptop, or at the screen of your iPhone. I don't care what kind of things you've done in life, or how many mistakes you've made, YOU ARE A F**KIN BADASS. Keep doing what you're doing.
Someone who is absolutely amazing and exhibits the traits of being worthy of awe! Perfection at it's greatest. When one is considered to be amazing, it can be inferred that they are also amazing, cool, beautiful, and fantastic. See Example.