I am definitely badass !

it can also mean someone who is overly confident and cocky in their abilities, either being above something (like the powers that be) or the ability to do something (sometimes this includes fighting abilities). Example: Danny tried to jump over the car because he's a badass and doesn't know any better.

It is slang. It is the same as ´´awesome´´ or ´´cool´´.... When someone does something spectacular we can use ´´that was badass´´