Prior to (6)
I believe the answer is:
before
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">prior to</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for before that I've seen before include "Prior to" , "Defy, withstand" , "In advance" , "In sight of" , "In front of (something)" .)