[Bakary]

I would define it as a positive feedback loop that is a mix of authenticity, energy, personality, desire, boldness, desire and will. There is perhaps a better word for it, but generally a person that exemplifies some of the strongest characteristics of human life as instinctively recognized by humans themselves.

As a corollary, such people tend to be naturally charismatic, but I would venture that this is a direct consequence of their other traits. One arresting definition of charisma I have heard is that it is a measure of how much you can delineate yourself as an entity in the world and how you can use that to affect reality. Life-affirmation and a zest for living draw directly into that.

Note that I don't necessarily include intellectual brilliance in the equation, though it obviously helps.