Assessor (6)
I believe the answer is:
valuer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">assessor</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for valuer that I've seen before include "A professional assessor of commercial worth" , "Assessor of the worth of things" .)