Source : Webster's Revised Unabridged Dictionary (1913)

Whiten \Whit"en\, v. i. [imp. & p. p. {Whitened}; p. pr. & vb.
   n. {Whitening}.] [OE. whitenen; cf. Icel. hv[=i]tna.]
   To grow white; to turn or become white or whiter; as, the
   hair whitens with age; the sea whitens with foam; the trees
   in spring whiten with blossoms.

Source : WordNet®

whitened
     adj : (of hair) having lost its color; "the white hairs of old
           age" [syn: {white}]