The Collaborative International Dictionary of English v.0.48:

Knight-errantry \Knight"-er`rant*ry\, n.; pl.
   Knight-errantries.
   The character or actions of wandering knights; the practice
   of wandering in quest of adventures; chivalry; a quixotic or
   romantic adventure or scheme.
   [1913 Webster]

         The rigid guardian [i. e., conscience] of a blameless
         heart
         Is weak with rank knight-erratries o'errun. --Young.
   [1913 Webster]