Source : Webster's Revised Unabridged Dictionary (1913)

Quixotism \Quix"ot*ism\, n.
   That form of delusion which leads to extravagant and absurd
   undertakings or sacrifices in obedience to a morbidly
   romantic ideal of duty or honor, as illustrated by the
   exploits of Don Quixote in knight-errantry.

Source : WordNet®

quixotism
     n : quixotic (romantic and impractical) behavior [syn: {knight
         errantry}]