And of course there's the stupidly long word with no real need to exist, antidisestablishmentarianism. Favorite of a friend who tried to impress everyone by rattling it off in conversation every once in a while, without it pertaining to the sentence in any way...
I once saw at least a derivative of that word used correctly in a British newspaper. FWIW, I read it because I'm an Episcopalian and the word relates to the Anglican Church, from which we stem.
Want an explanation? Warning, technical and possibly dull...
The United Kingdom has an "established" (official) church, the Church of England (a/k/a Anglican Church), going back to the days of Henry VIII. (As you may remember, he wanted to get rid of wife #1 in favor of a hot younger one; since the Catholic Church wouldn't agree to annul his marriage, he decided to start his own national church, owned and run by him.) The reigning king or queen is always the head of the Church of England, rather like the Pope for Catholics... and regardless of his or her personal behavior. (By law, the monarch and heirs to the throne *have* to be Church of England, or they get taken out of the lineup.)
"Establishmentarian" is the adjective meaning "in favor of England's established church" -- including keeping the monarch as its head -- and "e... ism" is the noun form of that.
DIS-establishment is the position that England (now a multi-cultural society with low church attendance rates) shouldn't have an official church ruled by the head of state, any more than the U.S. does. It's a long word, but a valid one, and shows up from time to time in high-minded publications like the Economist and the Guardian.
ANTI-disestablishment is kind of an absurd extension. But you could say it means "opposing the people who want to get rid of England's established church."
Here endeth today's lesson.