This was a word made up by the folks who produced the movie Mary Poppins. If you listen to the lyrics it says if you say it loud enough you'll always sound precocious. And Precocious only means: Manifesting or characterized by unusually early development or maturity, especially in mental aptitude... So, you'll sound smarter than your years.
It's a nonsensical word that baffles people into thinking you're smarter than you actually are.
Hows the market going to go today Jim?
I think it's going to be Supercalifragilisticexpialidocious!
Great, I be sure to put some money in today then Jim. Thanks for the tip!