Commercial endorsement (4)
I believe the answer is:
plug
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">commercial endorsement</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for plug that I've seen before include "Wad of tobacco and electrical accessory" , "Power point" , "See 19" , "Stopper - connector" , "Promote" .)