The Collaborative International Dictionary of English v.0.48:

Guerdon \Guer"don\, n. [OF. guerdon, guerredon, LL. widerdonum
   (influenced by L. donum gift, cf. Donation ), fr. OHG.
   widarl[=o]n; widar again, against (G. wider wieder) + l[=o]n
   reward, G. lohn, akin to AS. le['a]n Goth. laun. See
   Withers.]
   A reward; requital; recompense; -- used in both a good and a
   bad sense. --Macaulay.
   [1913 Webster]

         So young as to regard men's frown or smile
         As loss or guerdon of a glorious lot.    --Byron.
   [1913 Webster]

         He shall, by thy revenging hand, at once receive the
         just guerdon of all his former villainies. --Knolles.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Guerdon \Guer"don\, v. t. [OF. guerdonner, guerredonner. See
   Guerdon, n.]
   To give guerdon to; to reward; to be a recompense for. [R.]
   [1913 Webster]

         Him we gave a costly bribe
         To guerdon silence.                      --Tennyson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

guerdon
    n 1: a reward or payment