Source : Webster's Revised Unabridged Dictionary (1913)

Overstate \O`ver*state"\, v. t. [imp. & p. p. {Overstated}; p.
   pr. & vb. n. {Overstating}.]
   To state in too strong terms; to exaggerate. --Fuller.

Source : WordNet®

overstate
     v : to enlarge beyond bounds or the truth; "tended to
         romanticize and exaggerate this `gracious Old South'
         imagery" [syn: {exaggerate}, {overdraw}, {hyperbolize}, {hyerbolise},
          {magnify}, {amplify}] [ant: {understate}]