Definition of "Quixote"

I had once determined to fix the terrible Name of some Man of War in the Front of your History, a perfect Hero, that should like another Quixot defend your Reputation right, or wrong [...].

1723, Charles Walker, Sally Salisbury

Few things can more inflame / This far too combative heart / Than the intellectual Quixotes of the age / Prattling of abstract art.

1929, Cecil Day Lewis, Transitional Poem