Impress (5)
I believe the answer is:
stamp
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">impress</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that impress is the is a more specific form of the action of stamp.)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stamp that I've seen before include "Imprinted mark" , "Use a die; character" , "One has picture of Queen" , "Impress with a mark" , "squash?" .)