The Collaborative International Dictionary of English v.0.48:

Longspun \Long"spun`\, a.
   Spun out, or extended, to great length; hence, long-winded;
   tedious.
   [1913 Webster]

         The longspun allegories fulsome grow,
         While the dull moral lies too plain below. --Addison.
   [1913 Webster]