Plumber's friend? (7)
I believe the answer is:
plunger
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">plumber's friend?</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for plunger that I've seen before include "Drain unblocker" , "Sink unblocker" , "Rubber pipe unblocker" , "Better" , "Plumber's friend" .)