knight errant

Noun

knight-errant (plural knights-errant)

1. A knight in a medieval romance who wanders in search of adventure and opportunities to prove his chivalry.
   • In short, his wits being quite gone, [Don Quixote] hit upon the strangest notion that ever madman in this world hit upon, and that was that he fancied it was right and requisite, as well for the support of his own honour as for the service of his country, that he should make a knight-errant of...1885, John Ormsby, chapter 1, in Don Quixote, volume 1, translation of original by Miguel de Cervantes
2. A person who displays an adventurous or a quixotic spirit.
   • "Welcome, my young knight-errant!" exclaimed Madame de Soissons. "I am expecting you to do wonders." "Nothing could be wonderful when performed in your service," replied the boy, with that readiness of compliment so characteristic of his time and court.1834, L[etitia] E[lizabeth] L[andon], chapter XLI, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), →OCLC, page 341