Tester (8)
I believe the answer is:
examiner
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tester</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that tester can be written as examiner)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for examiner that I've seen before include "One in charge of test" , "bloke who will make inspection" , "One setting a formal test" , "Assessor" , "Tester of knowledge" .)