The Collaborative International Dictionary of English v.0.48:

Appraiser \Ap*prais"er\, n. [See Appraise, Apprizer.]
   One who appraises; esp., a person appointed and sworn to
   estimate and fix the value of goods or estates.
   [1913 Webster]

WordNet (r) 3.0 (2006):

appraiser
    n 1: one who estimates officially the worth or value or quality
         of things [syn: appraiser, valuator]
    2: one who determines authenticity (as of works of art) or who
       guarantees validity [syn: appraiser, authenticator]