adj. A word from the Disney film production of the book Mary Poppins describing any quality that is so indescribable that you have no real word to say it with

A fictitious word introduced in Mary Poppins. Thought to be a nonsense word, but it contains elements of real Greek and Latin roots:

super: above, over, extreme
cali: beauty
fragilistic: delicate
expiali: to atone, to make amends
docious: educable, able to learn

Multiple mispellings refer to the correctly spelled word "Supercalifragilisticexpialidocious" - a nonsense word uttered by the character, Mary Poppins in the 1964 movie of the same name. The Walt Disney production of the film, starring Julie Andrews as Mary Poppins, featured the word in a song that tells how you can use it to impress others or as an exclamation when you don't know what to say. (The movie, Mary Poppins, was based on the book of the same title, written by P L Travers in 1934.)

If you say it loud enough, you'll aways sound precocious.

The roots of the word have been defined as follows: super- "above", cali- "beauty", fragilistic- "delicate", expiali- "to atone", and docious- "educable".
With the sum of these parts signifying roughly "Atoning for educability through delicate beauty."

Used as a nonsense word by children to express approval or to represent the longest word in English.

soo-per-kal-uh-fraj-uh-lis-tik-ek-spee-al-i-doh-shuhs

so long...lol

Adj. a nonsense word meaning fantastic; also called supercalifragilistic

It's a ficticious word that you say when you want to sound precocious or when your tongue tied and need to come up with something impressive.