It's meant to be a nonsensical, yet grand-sounding word used to express something:
* Wonderful: The characters in the movie use it to describe something fantastic or amazing.
* Exceedingly good: It carries the feeling of being exceptionally great or impressive.
It's essentially a catchy, playful way to express awe and delight, with no real dictionary definition.
The word's popularity has made it a staple of English language, even though it has no true meaning.