Adjective; Antonyms include Hella Cool, Nigga, African-American, and the like.
1. Describes anybody who is cool, but not black.
2. Describes any non-black person with a stereotypical black personality.
White guy: Hello, my mexican friend. You're looking Hecka Cool today!
Mexican guy: Why thank you, my white buddy. You're looking Hecka Cool yourself, yo G dawg. But NOT Hella Cool, because then you'd be black. ...And you're white.