Pins down (5)
I believe the answer is:
nails
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">pins down</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 nails that I've seen before include "Filed regularly" , "Slain with metal pins" , "they may provide security for the board" , "Horny plates of the digits" , "Fastens with spikes" .)