Advert; vehicle (7)
I believe the answer is:
trailer
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">advert</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that trailer is a type of advert)</span><br/ ><br/ >'<span class="explanation-format__original">vehicle</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that trailer is a type of wheeled vehicle)</span><br/ ><br/ ></span>
(Other definitions for trailer that I've seen before include "commercial vehicle drawn along" , "Short film advertising programme" , "vehicle without power" , "Towed vehicle; advertisement" , "house on wheels" .)