noun
A person who professionally evaluates authenticity, quality, or value, especially of art, antiques, or collectibles.
彼は美術品の鑑定家として有名だ。
He is famous as an appraiser of artworks.
鑑定家に壺の価値を調べてもらった
I had an appraiser examine the value of the pot.
Compound of 鑑定 (appraisal, judgment) and 家 (person, expert). The exact historical derivation is uncertain, but the word follows a common pattern for forming occupational nouns.