The Collaborative International Dictionary of English v.0.48:

Warn \Warn\ (w[add]rn), v. t. [OE. wernen, AS. weornan, wyrnan.
   Cf. Warn to admonish.]
   To refuse. [Written also wern, worn.] [Obs.] --Chaucer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wern \Wern\, v. t. [See 1st Warn.]
   To refuse. [Obs.]
   [1913 Webster]

         He is too great a niggard that will wern
         A man to light a candle at his lantern.  --Chaucer.
   [1913 Webster]