Advertise; stopper (4)
I believe the answer is:
plug
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">advertise</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that plug is a more specific form of the action advertise)</span><br/ ><br/ >'<span class="explanation-format__original">stopper</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that stopper can be written as plug)</span><br/ ><br/ ></span>
(Other definitions for plug that I've seen before include "Cork" , "Publicise -- stop" , "Shoot" , "It fits into electric socket" , "Stopper - advertise" .)