Source : Webster's Revised Unabridged Dictionary (1913)

Overvalue \O`ver*val"ue\, v. t. [imp. & p. p. {Overvalued}; p.
   pr. & vb. n. {Overvaluing}.]
   1. To value excessively; to rate at too high a price. ``To
      overvalue human power.'' --Holyday.

   2. To exceed in value. [R.] --H. Brooke.

Source : WordNet®

overvalue
     v : assign too high a value to; "You are overestimating the
         value of your old car" [syn: {overestimate}] [ant: {undervalue},
          {undervalue}]