Source : Webster's Revised Unabridged Dictionary (1913)

Grizzled \Griz"zled\, a.
   Gray; grayish; sprinkled or mixed with gray; of a mixed white
   and black.

         Grizzled hair flowing in elf locks.      --Sir W.
                                                  Scott.

Source : WordNet®

grizzled
     adj : having dark hairs mixed with gray or white