It's kind of a joke. It's one of a number of candidates for "the longest word in the English language." It's the longest non-technical word in the Oxford English Dictionary, so it counts as a word. It supposedly means the "habit of judging something as worthless." But I have never seen it used except in discussions of "the longest word in the English language." "Antidisestablishmentarianism" is a little bit more of a "real word." I imagine that it really was used in England in the 1800s. The Church of England has an official status in England. It is the "established church." Before 1828 you actually had to be a member of that church to hold public office. Nowadays England is almost a secular state, but not quite--the Queen is sworn to uphold Christianity, and so forth. In any case, there was a movement to "disestablish" the Church of England, its members were "disestablishmentarians," their opponents were "antidisestablishmentarians," and their viewpoint was "antidisestablishmentarianism." The word "supercalifragilisticexpialidocious" was coined by the Sherman brothers for a song in the 1964 movie, "Mary Poppins." Many children have seen the movie, many have come to think that it's a real word, and some people believe it's the longest word in English. It's not in dictionaries yet. My personal feeling is that it is just as "real" as floccinaucinihilipilification"--i.e. not very real--and perhaps someday lexicographers will decide to include it in dictionaries.

https://en.wiktionary.org/wiki/floccinaucinihilipilification -- it's a jocular coinage, OK? it means "Zinnober" in German

I've encountered the word before, but only as a fun word to learn. More well known, and longer as well, is "pneumonoultramicroscopicsilicovolcanoconiosis," which refers to a lung disease caused by dust from a volcano. One of my fifth grade students taught me the word about 15 years ago, and after that I always taught it to all my students. I can't answer your question better than dictionary.com: floccinaucinihilipilification [flok-suh-naw-suh-nahy-hil-uh-pil-uh-fi-key-shuh n] Rare. the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language). I can help you with many other questions, however, if you would like to sign up for classes!

Something that doesn't have any value. Lol