Postage label (5)
I believe the answer is:
stamp
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">postage label</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for stamp that I've seen before include "Bring foot down hard" , "Impress; postage sticker" , "put one's foot down hard" , "Validation for a letter - tread heavily" , "making an impression?" .)