What makes the word "quixotic" so interesting? Well, the fact that it contains both a "Q" and an "X," of course. According to one English language word list I checked, there are only 26 words in the English language which contain both of those letters, and of those 26, nine of them are variations on "quixotic" (quixotically, quixotry, quixotism, etc).
Okay, so that's not really what's interesting about the word. The word is directly derived from the name of a character in what is perhaps the most famous piece of Spanish literature. Do you know who it is? Do you need a hint?
A novel by Cervantes. That contains windmills.
Yes, that's right. Don Quixote. Don Quixote was a somewhat crazy individual who read too many stories of the age of chivalry, and decided to go out into the world righting wrongs, fighting evil, and delivering justice wherever needed. The famous expression "tilting at windmills" is a reference to Don Quixote attacking some windmills because he believed them to be giants.
He was hopelessly hopeful, absurdly optimistic, and impractically idealistic.
And that's the definition of the word "quixotic." To be quixotic is to be exceedingly idealistic, unrealistic, and impractical.
Oh, and just so you don't stumble over the pronunciation, even though Quixote is pronounced kay-HO-tay, "quixotic" is not pronounced kay-HO-tic. It's kwix-OT-ic.