Several decades ago, all through my school days, strong emphasis was put on spelling . Each year the school would promote and have a spelling bee. Students would enter the competition and be given very difficult words to spell. These competitions became state and national, as well as local tournaments. As long as you spelled correctly, you stayed in the game and you continued to stand, but one miss, and you took your seat. Some words were short and tough, but most were big, long, words. This word, antidisestablishmentarianism was given to the two final national contestants; one missed and one didn't and we had a new Spelling Bee World Champion.
I've always remembered this word.
Its meaning, according to Merriam-Webster, is a philosophy that opposes disestablishment, i.e., the deprivement of an established status; not so easy to remember