Quixotic

While it is most often used to mean equally impractical and idealistic, it also has the sense of romantic nobility. Its source is the Spanish novel Don Quixote, whose title character is given to unrealistic schemes and great chivalry, and fights noble but imaginary battles against giants and windmills. This is also the origin of the phrase "tilting at windmills", meaning attacking imaginary enemies.

Further Reading

• The History of Don Quixote | Gutengberg
• Don Quixote by Miguel de Cervantes | The Literature Network
• Fighting windmills: the many interpretations of Don Quixote | University of Cambridge