Don Quixote, the classic novel by Spanish writer Miguel de Cervantes, has a few synonyms that have thus been derived from the title character. The most common is "quixotic", which describes someone who is often impractical or overly ambitious in his or her endeavors. Another is "tilting at windmills", which references a famous scene from the book where the protagonist fights imagined enemies, and is now used to describe someone who is fighting against something that doesn't actually exist. Finally, "Don Quixote syndrome" is used to describe someone who has a delusional belief in his or her own abilities, despite evidence to the contrary.