Also, from Urban Dictionary:
A thug that has "made it" to the big time. Originally refered [sic] ball players that made it out of the streets to make millions as a pro ball player, but now is used to describe any thug that is living large.
(Note: The man pictured at the link is not baller.)
This is a word Old People shouldn't use unless they have a full grasp on the understanding. Because its etymology is rooted in urban and hip hop culture, Old People are especially prone to looking...old when the word is misused. Moreover, when a word is rooted in urban slash hip hop culture, and a person of privilege uses it, the person risks looking insensitive or rude.
Not that a person outside the person can't use it. In the interest of honesty, I've been working the word in to my regular conversation in the interest of personally reviving it in my social circle. Because the correct opportunities have not arisen, I've reserved baller for non-baller situations, like, These Oreos are baller. DO NOT DO THIS.
Baller, Urban Dictionary
Baller, The Online Slang Dictionary
Baller Alert, "For women who want the ballerific life!"