Adjuster (5)
I believe the answer is:
tuner
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">adjuster</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I have seen 'Adjuster of pianos ' mean 'tuner' so perhaps 'adjuster' could also mean 'tuner')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tuner that I've seen before include "Radio receiver" , "Motor specialist" , "Radio adjuster" , "Adjuster of pianos" , "Piano adjuster" .)