Generally refers to a male. Confident, secure, uninhibited, so cool it hurts, hardcore, independent – all in one. I guess the character of James Bond is expected to be badass.
Sometimes referred to a woman. Means being down to earth, daring, confident unafraid of challenge (not intellectual but the challenge of real life experience – sports, extreme experiences, edgy actions). I guess they refer badass to a woman who looks quite tender and feminine so that they do not expect her to keep her senses facing a challenge. maybe a badass woman is an attractive female who behaves unexpectedly confidently in unusual situation.
Shia LaBeouf on Michelle Monaghan in Eagle Eye: "She's badass."