"Popularized in a Missy Elliott song by the same name..."
Fucking tweens and 20 somethings need to stop applying retarded, wishful definitions to words that were around before their birth. "Dealio" was not popularized by missy elliot, as it has been used consistently 20+ years before her music career got off the ground.
What's the deal? Wuzzup? What it is? What it will be? What's gonon?, What's REALLY gonon? Wuzapnin? What's this all about? What's the time? What's next? Who's next?
But with a little flair. Can be:
1) a little more intimidating, as in toying with someone. (Tell me the truth.) Or,
2) just trying to sound cool (sometimes sounds FOOL or like a prick).
1) DX: "So tell me Regina. You sez you at home all night; but, my boyz seen you riding the Avenues in a black Beamah! Now ... WHAT'S THE DEALIO?!"
2) COOLIO FOOLIO: "WHAT'S THE DEALIO, Emilio? Sound like a shoddy old audio. Maybe we oughta BURY yo' stereo!"