Hard kick (4)
I believe the answer is:
boot
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hard kick</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 boot that I've seen before include "Dismiss" , "Kick; footwear" , "Stout shoe" , "Sack" , "Clothing; kick" .)