I recently ran into a word that I hadn't encountered before in my life in this context:
"Well, thanks a lot [BlackVegetable] both for your quick reply and disponibility."
(It's in a comment on Stack Overflow.)
Intrigued, I performed a quick Google search on the word "Disponibility" which led me to the Wiktionary entry stating:
What on earth? I thought I would have encountered this in a thesaurus or some other context for such a common word by now. When is this word (supposed to be) used, and is it an exact synonym?